This question tests 2nd grade understanding of odd and even numbers, including determining whether a whole number up to 20 (or 100) is odd or even (CCSS 2.OA.C.3: Determine whether a group of objects (up to 20) has an odd or even number of members). Even numbers can be divided into two equal groups with no leftovers, or paired completely with no one left out. Even numbers end in 0, 2, 4, 6, or 8 in the ones place. Examples: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. Odd numbers cannot be divided into two equal groups without a remainder—when you try to pair them, there's always one left over. Odd numbers end in 1, 3, 5, 7, or 9 in the ones place. Examples: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19. Visual test: can you arrange objects in exactly 2 equal rows? If yes, even; if no (one row has extra), odd. In this problem, the student must identify which number from a list is even. To identify, check the ones digit of each—12 ends in 2 (even), while 11 ends in 1 (odd), 15 in 5 (odd), 19 in 9 (odd). Choice B is correct because 12 is even—it ends in 2 which is an even digit, or can pair 12 objects completely (6 pairs, no leftover). This correctly applies the definition of even (can pair completely, ends in 0,2,4,6,8) or odd (one leftover, ends in 1,3,5,7,9). Choice A represents selecting wrong numbers (asked for even, gave odd numbers or mixed). This error typically happens when students confuse odd/even definitions, look at wrong digit, don't understand pairing concept, miscount, reverse the patterns, don't know which digits are even/odd. To help students: Teach concrete pairing method first—give students 14 counters, have them pair up: 'Can you make pairs? Any left over? None left—that's even!' Repeat with 15 counters: 'One left over—that's odd!' Introduce digit rule: 'Even numbers end in 0, 2, 4, 6, or 8. Odd numbers end in 1, 3, 5, 7, or 9.' Practice identifying: show number, ask 'What's the ones digit? Is that even or odd?' Use visual arrays: 'Can we make exactly 2 equal rows? Yes=even, No=odd.' Show hundred chart: highlight all even numbers (0,2,4,6,8 in ones place), notice pattern—they form columns. Practice counting by 2s: 2, 4, 6, 8, 10, 12—all even! Connect to real life: 'We have 15 students. Can everyone find a partner? Let's try—oh no, one person left! 15 is odd.' Teach rhyme/memory: 'Even is neat—all paired up; Odd's left one out, odd one standing up!' or 'Zero and the EVEN numbers: 0,2,4,6,8; The ODD ones 1,3,5,7,9—let's celebrate!' Practice sorting: mix of numbers, sort into even and odd piles. Watch for: looking at wrong digit (tens instead of ones), reversing definitions, confusing which digits are even/odd, miscounting objects, not understanding pairing/leftover concept.

This question tests 2nd grade understanding of odd and even numbers, including determining whether a whole number up to 20 is odd or even (CCSS 2.OA.C.3: Determine whether a group of objects (up to 20) has an odd or even number of members). Even numbers can be divided into two equal groups with no leftovers, or paired completely with no one left out; even numbers end in 0, 2, 4, 6, or 8 in the ones place, with examples like 2, 4, 6, 8, 10, 12, 14, 16, 18, 20; odd numbers cannot be divided into two equal groups without a remainder—when you try to pair them, there's always one left over; odd numbers end in 1, 3, 5, 7, or 9 in the ones place, with examples like 1, 3, 5, 7, 9, 11, 13, 15, 17, 19; visual test: can you arrange objects in exactly 2 equal rows? If yes, even; if no (one row has extra), odd. In this problem, the student must determine if 17 is odd or even; to identify, check the ones digit of 17—it's 7, which means odd (7 is in the list 1,3,5,7,9), or try pairing 17 objects—make 8 pairs with one left over, so odd. Choice B is correct because 17 is odd—it ends in 7 which is an odd digit, or cannot pair 17 objects completely (8 pairs, one leftover); this correctly applies the definition of odd (one leftover, ends in 1,3,5,7,9). Choice A represents reversed classification (said 17 is even when it's odd—may have confused definitions); this error typically happens when students confuse odd/even definitions, look at the wrong digit, or don't understand the pairing concept. To help students: Teach concrete pairing method first—give students 14 counters, have them pair up: 'Can you make pairs? Any left over? None left—that's even!' Repeat with 15 counters: 'One left over—that's odd!' Introduce digit rule: 'Even numbers end in 0, 2, 4, 6, or 8; odd numbers end in 1, 3, 5, 7, or 9.' Practice identifying: show number, ask 'What's the ones digit? Is that even or odd?' Use visual arrays: 'Can we make exactly 2 equal rows? Yes=even, No=odd.' Show hundred chart: highlight all even numbers (0,2,4,6,8 in ones place), notice pattern—they form columns; practice counting by 2s: 2, 4, 6, 8, 10, 12—all even! Connect to real life: 'We have 15 students; can everyone find a partner? Let's try—oh no, one person left! 15 is odd.' Teach rhyme/memory: 'Even is neat—all paired up; Odd's left one out, odd one standing up!' or 'Zero and the EVEN numbers: 0,2,4,6,8; The ODD ones 1,3,5,7,9—let's celebrate!' Practice sorting: mix of numbers, sort into even and odd piles; watch for: looking at wrong digit (tens instead of ones), reversing definitions, confusing which digits are even/odd, miscounting objects, not understanding pairing/leftover concept.

This question tests 2nd grade understanding of odd and even numbers, including determining whether a whole number up to 20 is odd or even (CCSS 2.OA.C.3: Determine whether a group of objects (up to 20) has an odd or even number of members). Even numbers can be divided into two equal groups with no leftovers, or paired completely with no one left out; even numbers end in 0, 2, 4, 6, or 8 in the ones place, with examples like 2, 4, 6, 8, 10, 12, 14, 16, 18, 20; odd numbers cannot be divided into two equal groups without a remainder—when you try to pair them, there's always one left over; odd numbers end in 1, 3, 5, 7, or 9 in the ones place, with examples like 1, 3, 5, 7, 9, 11, 13, 15, 17, 19; visual test: can you arrange objects in exactly 2 equal rows? If yes, even; if no (one row has extra), odd. In this problem, the student must determine if 14 is odd or even; to identify, check the ones digit of 14—it's 4, which means even (4 is in the list 0,2,4,6,8), or try pairing 14 objects—make 7 pairs with none left over, so even. Choice B is correct because 14 is even—it ends in 4 which is an even digit, or can pair 14 objects completely (7 pairs, no leftover); this correctly applies the definition of even (can pair completely, ends in 0,2,4,6,8). Choice A represents reversed classification (said 14 is odd when it's even—may have confused definitions); this error typically happens when students confuse odd/even definitions, look at the wrong digit, or don't understand the pairing concept. To help students: Teach concrete pairing method first—give students 14 counters, have them pair up: 'Can you make pairs? Any left over? None left—that's even!' Repeat with 15 counters: 'One left over—that's odd!' Introduce digit rule: 'Even numbers end in 0, 2, 4, 6, or 8; odd numbers end in 1, 3, 5, 7, or 9.' Practice identifying: show number, ask 'What's the ones digit? Is that even or odd?' Use visual arrays: 'Can we make exactly 2 equal rows? Yes=even, No=odd.' Show hundred chart: highlight all even numbers (0,2,4,6,8 in ones place), notice pattern—they form columns; practice counting by 2s: 2, 4, 6, 8, 10, 12—all even! Connect to real life: 'We have 15 students; can everyone find a partner? Let's try—oh no, one person left! 15 is odd.' Teach rhyme/memory: 'Even is neat—all paired up; Odd's left one out, odd one standing up!' or 'Zero and the EVEN numbers: 0,2,4,6,8; The ODD ones 1,3,5,7,9—let's celebrate!' Practice sorting: mix of numbers, sort into even and odd piles; watch for: looking at wrong digit (tens instead of ones), reversing definitions, confusing which digits are even/odd, miscounting objects, not understanding pairing/leftover concept.

This question tests 2nd grade understanding of odd and even numbers, including determining whether a whole number up to 20 (or 100) is odd or even (CCSS 2.OA.C.3: Determine whether a group of objects (up to 20) has an odd or even number of members). Even numbers can be divided into two equal groups with no leftovers, or paired completely with no one left out. Even numbers end in 0, 2, 4, 6, or 8 in the ones place. Examples: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20. Odd numbers cannot be divided into two equal groups without a remainder—when you try to pair them, there's always one left over. Odd numbers end in 1, 3, 5, 7, or 9 in the ones place. Examples: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19. Visual test: can you arrange objects in exactly 2 equal rows? If yes, even; if no (one row has extra), odd. In this problem, the student must identify which number from a list is odd. To identify, check ones digits: 8 ends in 8 (even), 12 ends in 2 (even), 15 ends in 5 (odd), 18 ends in 8 (even). Choice C is correct because 15 is odd (ends in 5)—there will be 1 leftover when pairing. This correctly applies the definition of even (can pair completely, ends in 0,2,4,6,8) or odd (one leftover, ends in 1,3,5,7,9). Choice A represents selected wrong numbers (asked for odd, gave even number). This error typically happens when students confuse odd/even definitions, look at wrong digit, don't understand pairing concept, miscount, reverse the patterns, don't know which digits are even/odd. To help students: Teach concrete pairing method first—give students 14 counters, have them pair up: 'Can you make pairs? Any left over? None left—that's even!' Repeat with 15 counters: 'One left over—that's odd!' Introduce digit rule: 'Even numbers end in 0, 2, 4, 6, or 8. Odd numbers end in 1, 3, 5, 7, or 9.' Practice identifying: show number, ask 'What's the ones digit? Is that even or odd?' Use visual arrays: 'Can we make exactly 2 equal rows? Yes=even, No=odd.' Show hundred chart: highlight all even numbers (0,2,4,6,8 in ones place), notice pattern—they form columns. Practice counting by 2s: 2, 4, 6, 8, 10, 12—all even! Connect to real life: 'We have 15 students. Can everyone find a partner? Let's try—oh no, one person left! 15 is odd.' Teach rhyme/memory: 'Even is neat—all paired up; Odd's left one out, odd one standing up!' or 'Zero and the EVEN numbers: 0,2,4,6,8; The ODD ones 1,3,5,7,9—let's celebrate!' Practice sorting: mix of numbers, sort into even and odd piles. Watch for: looking at wrong digit (tens instead of ones), reversing definitions, confusing which digits are even/odd, miscounting objects, not understanding pairing/leftover concept.

14 is even because it can be divided into two equal groups with no remainder (7 + 7 = 14). When a number can be shared equally between two people with nothing left over, it is even. Choice B incorrectly identifies 14 as odd based on irrelevant factors. Choice C contradicts itself by saying numbers ending in 4 are odd. Choice D incorrectly claims 14 is skipped when counting by 2s (2, 4, 6, 8, 10, 12, 14...).

When counting by 2s, Jake adds 2 to each number: 20 + 2 = 22. Since 22 = 11 + 11 (two equal addends), it is even and fits perfectly in the pattern. All numbers in the counting-by-2s sequence are even. Choice A gives the wrong next number and incorrectly calls it odd. Choice C gets the right number but wrongly calls 22 odd. Choice D skips ahead too far to 24.

When arranging 15 buttons in rows of 2, Sarah gets 7 complete rows (7 × 2 = 14 buttons) with 1 button remaining. This leftover button shows that 15 is odd - odd numbers always have a remainder when divided by 2. Choice B incorrectly calculates 8 rows and wrong classification. Choice C miscalculates as 6 rows with 3 left over. Choice D is wrong because all whole numbers are either odd or even.

Tom has 8 pairs (8 × 2 = 16 marbles) plus 1 leftover marble, giving him 17 marbles total. 17 is odd because when you try to pair all the marbles, one is left without a partner. Choice A correctly calculates 17 but wrongly calls it even. Choice B miscalculates the total as 16. Choice D incorrectly thinks he has 9 marbles by confusing pairs with individual marbles.

If sharing equally between 2 people leaves 1 leftover, Emma has an odd number of stickers. 13 ÷ 2 = 6 remainder 1, which matches the condition. Odd numbers always leave remainder 1 when divided by 2. Choice A: 12 ÷ 2 = 6 remainder 0, not 1. Choice B: 16 is even so divides evenly with no remainder. Choice D: 14 ÷ 2 = 7 remainder 0, not 1.

When you add any whole number to itself, the result is always even because it represents two equal groups. This connects to the definition that even numbers can be written as a sum of two equal addends. Choice A incorrectly identifies the sums as odd. Choice C is wrong because ALL such sums are even, not some. Choice D gives an incorrect reason - the number of addends doesn't determine if the sum is even or odd.