1st Grade Math Quiz: The Tens Digit
20 questions · exam conditions
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The Tens DigitQuestion 1 of 20

Look at 80. How many ones are in 80?

8
80
0
10
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1st Grade Math Quiz

1st Grade Math Quiz: The Tens Digit

Practice The Tens Digit in 1st Grade Math with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on The Tens Digit, giving you a quick way to practice the rules, question types, and explanations that matter most for 1st Grade Math.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

Look at 80. How many ones are in 80?

  1. 8
  2. 80
  3. 0 (correct answer)
  4. 10
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 80 is 8 tens and 0 ones, which we can see by showing 8 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus asks to look at 80 and identify how many ones are in it. Choice C is correct because 80 has exactly 0 ones, following the decade pattern. Choice A is a common error where students think the tens digit is the ones (says 8 ones); this happens because place value is abstract and students reverse tens and ones. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (80 vs 88: both have 8 tens, but 88 also has 8 ones); write equations showing 8 tens + 0 ones = 80; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 2

Look at 80 shown with 8 ten-rods and 0 ones. How many ones are in 80?

  1. 8
  2. 80
  3. 0 (correct answer)
  4. 10
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 80 is 8 tens and 0 ones, which we can see by showing 8 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus shows 80 represented with 8 ten-rods and no unit cubes. Choice C is correct because 80 is composed of 8 tens and 0 ones, shown by 8 ten-rods. Choice A is a common error where students reverse tens and ones (think 8 ones instead of 0); this happens because the 0 in ones place is sometimes overlooked and students confuse decade structure with teen structure. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (80 vs 88: both have 8 tens, but 88 also has 8 ones); write equations showing 8 tens + 0 ones = 80; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 3

Sofia has 30 as 3 bundles of 10 and 0 loose sticks. How many ones?

  1. 3
  2. 30
  3. 0 (correct answer)
  4. 10
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 30 is 3 tens and 0 ones, which we can see by showing 3 bundles of 10 sticks with no loose sticks; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus shows 30 represented with 3 bundles of 10 sticks and no loose sticks. Choice C is correct because 30 is composed of 3 tens and 0 ones, shown by 3 bundles. Choice A is a common error where students reverse tens and ones (think 3 ones instead of 0); this happens because the 0 in ones place is sometimes overlooked and students confuse decade structure with teen structure. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (30 vs 33: both have 3 tens, but 33 also has 3 ones); write equations showing 3 tens+0 ones=303 \text{ tens} + 0 \text{ ones} = 30; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 4

Look at 30. How many tens are in 30?

  1. 0
  2. 3 (correct answer)
  3. 30
  4. 4
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 30 is 3 tens and 0 ones, which we can see by showing 3 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus asks to look at 30 and identify how many tens are in it. Choice B is correct because 30 contains exactly 3 tens with 0 ones. Choice C is a common error where students count the total value instead of the number of tens (says 30 = 30 tens); this happens because students confuse the total count with the number of tens. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (30 vs 33: both have 3 tens, but 33 also has 3 ones); write equations showing 3 tens + 0 ones = 30; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 5

Sofia has 4 bundles of 10 sticks and 0 loose. How many ones?

  1. 0 (correct answer)
  2. 4
  3. 10
  4. 40
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 40 is 4 tens and 0 ones, which we can see by showing 4 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus describes Sofia having 4 bundles of 10 sticks and 0 loose, representing 40, and asks for the number of ones. Choice A is correct because there are exactly 0 ones, as stated with no loose sticks. Choice B is a common error where students think the number of tens is the number of ones (says 4 ones); this happens because the 0 in ones place is sometimes overlooked. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (40 vs 44: both have 4 tens, but 44 also has 4 ones); write equations showing 4 tens + 0 ones = 40; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 6

Keisha has 30 as 3 tens and 0 ones. How is 30 different from 35?

  1. 30 has 3 ones, but 35 has 0 ones
  2. 30 has 0 ones, but 35 has 5 ones (correct answer)
  3. 30 has 30 tens, but 35 has 3 tens
  4. 30 has 1 ten and 3 ones, but 35 has 3 tens
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 30 is 3 tens and 0 ones, while 35 is 3 tens and 5 ones; the digit in the tens place tells us how many tens, and the ones place differs by having 0 or more. The stimulus shows 30 represented with 3 ten-rods and no unit cubes, compared to 35. Choice B is correct because 30 has 0 ones, but 35 has 5 ones, highlighting the key difference in the ones place. Choice A is a common error where students reverse the ones for each number (says 30 has 3 ones and 35 has 0); this happens because place value is abstract and students overlook the 0 in ones place for decades. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (30 vs 35: both have 3 tens, but 35 also has 5 ones); write equations showing 3 tens + 0 ones = 30 vs 3 tens + 5 ones = 35; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 7

Maya shows 9 ten-rods and 0 ones. What number is shown?

  1. 90 (correct answer)
  2. 9
  3. 19
  4. 99
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 90 is 9 tens and 0 ones, which we can see by showing 9 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus describes Maya showing 9 ten-rods and 0 ones, and asks what number is shown. Choice A is correct because 90 is composed of 9 tens and 0 ones, shown by 9 ten-rods. Choice C is a common error where students confuse decade structure with teen structure (1 ten and 9 ones for 19); this happens because decade numbers look similar to teens but have different structure. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (90 vs 99: both have 9 tens, but 99 also has 9 ones); write equations showing 9 tens + 0 ones = 90; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 8

Look at 40 shown as 4 ten-rods and 0 ones. 40 is   tens and   ones.

  1. 4 tens and 0 ones (correct answer)
  2. 0 tens and 4 ones
  3. 4 tens and 4 ones
  4. 40 tens and 0 ones
Explanation: When you work with two-digit numbers, think of them as groups: each ten-rod stands for a bundle of 10, and each ones cube stands for a single 1. The number tells you how many bundles of ten and how many leftover ones you have. Here you can see 4 ten-rods and 0 ones cubes. Counting the tens gives 4 × 10 = 40, and there are no extra ones to add. So 40 is made of 4 tens and 0 ones — exactly what the picture shows. Now look at why the other choices don't fit. "0 tens and 4 ones" flips the picture backwards; that would only make 4, not 40. "4 tens and 4 ones" adds four extra ones that aren't in the picture, giving 44 instead of 40. "40 tens and 0 ones" confuses the whole number with the number of tens — but 40 tens would actually be 40 × 10 = 400, way too big. A helpful trick: in a two-digit number, the first digit tells you the tens and the second digit tells you the ones. In 40, the 4 is in the tens place and the 0 is in the ones place, so it must be 4 tens and 0 ones. Whenever you see ten-rods, just count the rods for tens and the loose cubes for ones.

Question 9

Look at 40 and 43. How are they different?

  1. 40 has 4 tens, 0 ones; 43 has 4 tens, 3 ones (correct answer)
  2. 40 has 0 tens, 4 ones; 43 has 0 tens, 43 ones
  3. 40 has 3 tens, 0 ones; 43 has 4 tens, 0 ones
  4. 40 has 4 tens, 4 ones; 43 has 4 tens, 3 ones
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 40 is 4 tens and 0 ones, while 43 is 4 tens and 3 ones; the digit in the tens place tells us how many tens, and the ones place differs by having 0 or more. The stimulus asks how 40 and 43 are different. Choice A is correct because 40 has 4 tens and 0 ones, while 43 has 4 tens and 3 ones, highlighting the difference in the ones place. Choice D is a common error where students include ones in the decade when there are none (says 40 has 4 ones); this happens because students confuse the total with place value or add extra ones. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (40 vs 43: both have 4 tens, but 43 has 3 ones); write equations showing 4 tens + 0 ones = 40 vs 4 tens + 3 ones = 43; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 10

Maya has 70 as 7 bundles of 10 and 0 loose ones. 70 is how many tens?

  1. 0
  2. 7 (correct answer)
  3. 70
  4. 8
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 70 is 7 tens and 0 ones, which we can see by showing 7 bundles of 10 sticks with no loose sticks; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus shows 70 represented with 7 bundles of 10 sticks and no loose sticks. Choice B is correct because 70 is composed of 7 tens and 0 ones, shown by 7 bundles. Choice C is a common error where students count the total value instead of number of tens (says 70 = 70 tens); this happens because place value is abstract and students confuse the total count with the number of tens. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (70 vs 77: both have 7 tens, but 77 also has 7 ones); write equations showing 7 tens + 0 ones = 70; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 11

Chen shows 6 ten-rods and 0 ones. How many tens is that?

  1. 0
  2. 5
  3. 6 (correct answer)
  4. 60
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 60 is 6 tens and 0 ones, which we can see by showing 6 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus describes Chen showing 6 ten-rods and 0 ones, and asks how many tens that is. Choice C is correct because there are exactly 6 tens, as shown by the 6 ten-rods. Choice D is a common error where students count the total value instead of the number of tens (says 60 tens); this happens because students confuse the total count with the number of tens. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (60 vs 66: both have 6 tens, but 66 also has 6 ones); write equations showing 6 tens+0 ones=606 \text{ tens} + 0 \text{ ones} = 60; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 12

Look at the number 50. It is   tens and   ones.

  1. 5 tens and 0 ones (correct answer)
  2. 0 tens and 5 ones
  3. 5 tens and 5 ones
  4. 50 tens and 0 ones
Explanation: When you see a two-digit number, each digit has a special job called its place value. The digit on the left tells you how many tens you have, and the digit on the right tells you how many ones. Think of tens as groups of 10 and ones as single leftover units. Look at 50. The digit on the left is 5, which sits in the tens place, so that means 5 tens. The digit on the right is 0, which sits in the ones place, so that means 0 ones. If you count 5 groups of ten, you get 10 + 10 + 10 + 10 + 10 = 50, which matches perfectly! So the answer is 5 tens and 0 ones. The choice "0 tens and 5 ones" flips the two digits around — that would actually spell the number 5, not 50. The choice "5 tens and 5 ones" adds an extra 5 ones, giving 50 + 5 = 55, which is too big. The choice "50 tens and 0 ones" confuses the whole number with the tens count — 50 tens would be 50 × 10 = 500, way too large. A helpful trick: for any two-digit number, just read it left to right. The first digit is your tens, and the second digit is your ones. Practice by covering one digit at a time and naming its place value — soon it will feel automatic!

Question 13

A number has 66 tens and 00 ones. Kim adds 33 tens to this number. How many tens does the new number have?

  1. The new number has 33 tens
  2. The new number has 66 tens
  3. The new number has 99 tens (correct answer)
  4. The new number has 3030 tens
Explanation: The original number has 6 tens (which is 60). Adding 3 tens means 6 + 3 = 9 tens total. Choice A shows only the tens added. Choice B shows only the original tens. Choice D incorrectly multiplies 6 × 3 = 18, then doubles it.

Question 14

Look at the pattern: 20,30,40,5020, 30, 40, 50. The tens in these numbers are 2,3,4,52, 3, 4, 5. If the pattern continues for two more numbers, how many tens will the last number have?

  1. The last number will have 66 tens
  2. The last number will have 77 tens (correct answer)
  3. The last number will have 6060 tens
  4. The last number will have 7070 tens
Explanation: The pattern of tens is 2, 3, 4, 5, and continues 6, 7. So the last number after two more steps will have 7 tens (which would be the number 70). Choice A gives the second-to-last number of tens. Choices C and D confuse the number of tens with the actual number value.

Question 15

Lily has 9090 stickers arranged in groups of ten. She gives away 3030 stickers to her friends. How many groups of ten does she have left?

  1. 66 (correct answer)
  2. 33
  3. 99
  4. 6060
Explanation: Lily starts with 9 groups of ten and gives away 3 groups of ten, leaving 6 groups. 3 is how many groups she gave away, not how many she has left. 9 repeats her starting number of groups without subtracting any. 60 mixes up the number of stickers with the number of groups. Only 6 correctly shows how many groups of ten Lily has left.

Question 16

Amir has 7 tens and 0 ones. What number is that?

  1. 7
  2. 70 (correct answer)
  3. 17
  4. 77
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 70 is 7 tens and 0 ones, which we can see by showing 7 ten-rods with no unit cubes; the digit in the tens place tells us how many tens, and the 0 in the ones place tells us there are no loose ones. The stimulus describes Amir having 7 tens and 0 ones, and asks what number that is. Choice B is correct because 70 is composed of 7 tens and 0 ones. Choice C is a common error where students confuse decade structure with teen structure (1 ten and 7 ones for 17); this happens because decade numbers look similar to teens but have different structure. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (70 vs 77: both have 7 tens, but 77 also has 7 ones); write equations showing 7 tens + 0 ones = 70; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 17

How is 40 different from 43?

  1. 40 has 4 tens and 0 ones (correct answer)
  2. 40 has 0 tens and 4 ones
  3. 40 has 4 tens and 3 ones
  4. 40 has 3 tens and 0 ones
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 40 is 4 tens and 0 ones, while 43 is 4 tens and 3 ones; we can see this by showing 4 ten-rods with no units for 40 versus adding 3 units for 43, highlighting the role of the ones place. The stimulus asks how 40 is different from 43, focusing on their place value composition. Choice A is correct because 40 has 4 tens and 0 ones, whereas 43 has 4 tens and 3 ones, showing the difference in ones. Choice C is a common error where students include ones when there are none (4 tens and 3 ones for 40, confusing it with 43); this happens because students miscount or blend the two numbers. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (40 vs 43: both have 4 tens, but 43 also has 3 ones); write equations showing 4 tens + 0 ones = 40; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 18

Chen has 3 tens and 0 ones. What number is it?

  1. 13
  2. 33
  3. 3
  4. 30 (correct answer)
Explanation: 3 tens and 0 ones makes the number 30. 13 mixes up the order of the tens and ones digits. 33 adds an extra 3 in the ones place that isn't there. 3 counts only the number of tens groups, not the value they represent. Only 30 correctly shows the number made from 3 tens and 0 ones.

Question 19

What do 10, 20, and 30 have in common?

  1. They all have 3 tens
  2. They all have 0 ones (correct answer)
  3. They all have 5 ones
  4. They are teen numbers
Explanation: This question tests 1st grade understanding that decade numbers (10, 20, 30...90) represent multiples of ten with 0 ones (CCSS.1.NBT.2.c). Decade numbers—10, 20, 30, 40, 50, 60, 70, 80, and 90—are special because they contain only tens and no ones. For example, 10 is 1 ten and 0 ones, 20 is 2 tens and 0 ones, and 30 is 3 tens and 0 ones; we can see this by showing ten-rods with no unit cubes, where the tens digit varies but ones is always 0. The stimulus asks what 10, 20, and 30 have in common. Choice B is correct because they all have 0 ones, a key feature of decade numbers. Choice A is a common error where students focus on one number's tens (3 tens for 30) instead of the shared trait; this happens because the 0 in ones place is sometimes overlooked. To help students: Use base-10 blocks extensively—show only ten-rods with explicit empty space where ones would be; emphasize 0 ones verbally and visually; practice counting by tens (10, 20, 30...90); connect decade numbers to skip counting; compare decades to non-decades (30 vs 33: both have 3 tens, but 33 also has 3 ones); write equations showing varying tens + 0 ones = decade; use place value charts highlighting the 0 in ones place; have students build each decade with blocks.

Question 20

Maya has 4 bundles of 10 straws and 0 loose straws. What number do the bundles represent?

  1. 4
  2. 44
  3. 40 (correct answer)
  4. 30
Explanation: 4 bundles of 10 straws make 40, since 4 tens equal 40. 4 counts only the number of bundles, not the value they represent. 44 mistakenly adds 4 loose straws that Maya doesn't have. 30 would only be 3 bundles of 10, not 4. Only 40 correctly matches 4 bundles of 10 with none left over.