All PSAT Math Resources
Example Questions
Example Question #492 : Arithmetic
45.728 x 3.2 = ?
1463.296
14632.96
146.3296
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 : How To Multiply Decimals
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
$10.40
$9.05
$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 #421 : Arithmetic
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 #422 : Arithmetic
0.0006
0.006
6
0.6
0.06
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 #1 : How To Multiply Decimals
At the store, green fabric costs $4.53 a yard. How much does 3.8 yards of green fabric cost? (Round to two decimal places.)
$17.22
$17.21
$17.13
$17.12
$17.31
$17.21
This is a simple multiplication problem involving decimals. Simply multiply 4.53 by 3.8:
Now, round to the nearest two decimal places, giving an answer of 17.21.
Example Question #4 : How To Multiply Decimals
Find the product. Round to the nearest hundredths place.
The hundredths place is the position two places to the right of the decimal. Our product is
. Rounding to the hundredths place results in .