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Example Questions
Example Question #4 : Decimals
45.728 x 3.2 = ?
1463.296
146.3296
14632.96
14.63296
146329.6
146.3296
Multiply the numbers out in long format, then move the decimal point over the total number of decimal points in the two numbers (3 in the first, 1 in the second, so 4 total):
45.728 * 3.2 = 91456
91456 + 1371840 = 1,463,296 → 146.3296
Or just count the decimal points in the answer and make sure it's 4.
Example Question #1 : Decimal Operations
At the farmer's market, oranges are $0.30 each, apples are $0.25 each, bananas are $0.40 each, and tomatoes are $0.60 each. If Scott buys 3 oranges, 7 apples, 4 bananas, and 8 tomatoes, how much does he spend?
$7.75
$11.40
$9.05
$10.40
$6.80
$9.05
To find out how much Scott spends, we need to multiply the quantity of each fruit by its price and add them all up.
3 * $0.30 + 7 * $0.25 + 4 * $0.40 + 8 * $0.60 = $9.05
Example Question #2 : Decimal Operations
If is 25% of
, what is the closest integer to the value of
?
We can approximate the value of y pretty quickly:
y ≈ 1(0.50)(52) = 26
Since y = 0.25x = (1/4)x we know that x = 4y ≈ 4(26) = 104
Example Question #2 : Decimal Operations
0.06
0.6
0.0006
6
0.006
0.006
It's much easier to work with whole numbers, so we'll ignore the decimals for the first step: 5 x 12 = 60
Now look at the decimals. To add them back in, think of 60 as 60.0. Now move the decimal point four places to the left: 0.5 x 0.012 = .0060 = .006
Example Question #2 : How To Multiply Decimals
You bought a dozen eggs marked at and received
change from
. What is the percent of sales tax?
Set the equation up as
Solve for , which equals
or
Therefore the percent sales tax is:
Example Question #4 : Decimal Operations
simplify: 0.2 ÷ 0.04
0.2 ÷ 0.04 <- easiest way to approach is to move the decimal to the right (the same amount of spaces on each side) so that the decimal disappears
since 0.04 has 2 spaces and 0.2 only has 1, move the decimal 2 spaces to the right on each side
0.2 ÷ 0.04 = 20 ÷ 4 = 5
Example Question #4 : Decimal Operations
If the cost of 20 equally priced pencils cost $5.80, then at the same rate what is the greatest number of pencils you can purchase for $50?
172.41
172
200
150
173
172
Remeber for this problem that you cannot spend more than $50. First find the price of each pencil by 5.80/20 = 29 cents. And then use this to do 50/0.29 = 172.41. So the greatest number of pencils you can purchase for $50 is 172 pencils.
Example Question #5 : Decimal Operations
Charlie has charges on his credit card of $63.70, $37.32, and $81.78. If he pays down half his bill at once, and then pays the rest in four equal monthly installments, how much is each monthly installment?
Adding all the charges together and dividing by 2 yields $91.40. Dividing this by 4 yields a monthly installment of $22.85.
Example Question #6 : Decimal Operations
Simplify:
Multiply both the numerator and denominator by some power of 10 to get rid of the decimals; in this case, multiply both by 10,000.
Example Question #1 : Ordering
Order the following decimals in order from least to greatest:
2.1, 6.9, 4.8, 5.2, 8.5
6.9, 4.8, 8.5, 5.2, 2.1
2.1, 5.2, 8.5, 4.8, 6.9
8.5, 6.9, 5.2, 4.8, 2.1
2.1, 4.8, 5.2, 6.9, 8.5
2.1, 4.8, 5.2, 6.9, 8.5
Look at the ones place first, ignoring the decimal. The order from greatest to least is 2, 4, 5, 6, and 8. Because none of the numbers in the ones place are the same, it doesn't matter what the decimal will be on these numbers- the order will remain the same. The order is 2.1, 4.8, 5.2, 6.9, 8.5.
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