How to divide decimals - PSAT Math

Card 0 of 6

Question

simplify: 0.2 ÷ 0.04

Answer

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

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Question

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?

Answer

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.

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Question

Simplify:

Answer

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.

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Question

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?

Answer

Adding all the charges together and dividing by 2 yields $91.40. Dividing this by 4 yields a monthly installment of $22.85.

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Question

Which number has 2.8 as its reciprocal?

Answer

The number that has 2.8 as its reciprocal is, in return, the reciprocal of 2.8.

The reciprocal of this can be found by switching the numerator and the denominator. This is .

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Question

23 grams of sodium are equal to atoms. How many atoms comprise one milligram of sodium?

(Select the closest answer)

Answer

23 grams are equal to 23,000 milligrams, so to find the number of atoms in one milligram, divide:

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