How to divide decimals

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SAT Math › How to divide decimals

Questions 1 - 4

simplify: 0.2 ÷ 0.04

0.005

0.05

0.02

Explanation

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

Simplify:

$\frac{0.004}{0.0005}$

Explanation

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.

$\frac{0.004}{0.0005}\cdot \frac{10,000}{10,000}=\frac{40}{5}=8$

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

173

172.41

200

150

Explanation

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.

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?

$\$22.85$