QuestenaPractice that shows what to review next
Topic lesson

Divide decimals by making the divisor whole

About 5 min

Questions stay in the language in which they were published.

These questions ask you to calculate decimal quotients, recognise equivalent divisions, and use division to count equal groups or recover a whole from a known part. First identify what is being divided and what size each group or part represents.

Make the divisor whole without changing the quotient

The divisor is the number after the division sign. If it is decimal, choose 10, 100, or another power of ten that makes it whole, then multiply both the dividend and divisor by that same number. For example, 5.6 ÷ 0.8 becomes 56 ÷ 8, which is 7. Moving both points together changes the scale of the two numbers but not their ratio.

When the divisor is already whole, keep it fixed and divide by place value. For example, 0.936 ÷ 6 is 0.156 because six groups of 0.156 make 0.936. To recover a whole from a known decimal share, divide the known part by that share: if 0.54 is 0.3 of a whole, then 0.54 ÷ 0.3 = 1.8. A multiplication check is especially useful here: quotient × divisor must reproduce the dividend.

Question signalOperation and check
How many equal pieces or groups fit?Divide the total by the size of one group.
A stated decimal part of a whole is knownDivide the known part by the decimal share to recover the whole.
The divisor lies between zero and oneExpect more than the dividend, because more small groups fit.
The divisor is greater than oneExpect less than the dividend when both values are positive.

Common wrong turns

Tempting routeHow to reject it
Multiply because the two numbers are beside an operationDivision asks how many groups fit or how large each share is. Multiply the proposed quotient by the divisor to see whether it returns the dividend.
Move the point in only one numberThat changes the ratio. Whatever power of ten is applied to the divisor must also be applied to the dividend.
Assume division must make a number smallerDividing by a proper decimal counts small groups, so the count grows. Dividing by one half, for example, asks how many halves fit.
Move both points by different numbers of placesUnequal scaling changes the quotient by a power of ten. Write the multiplier beside each number and verify that the multipliers match.
Use a nearby product for a quotient estimateKeep the original operation when choosing convenient numbers. Compatible values should make the division easy, not turn it into multiplication.

Try it

Question 76

Enter the quotient of 0.96 ÷ 0.3.

Question 79

A mass of 0.625 grams is shared equally among 5 samples. Enter the mass of each sample in grams.

Question 83

A science reading of 0.144 is 0.12 of a reference reading. Enter the reference reading.

Start drillPractice this topic
Divide decimals by making the divisor whole · Questena