Grade 6 › U03 Decimal Operations

Grade 6 › U03 Decimal Operations › L4
NUMBER · GRADE 6 · ALBERTAOUTCOME AB-MAT6-N4

L4 · Dividing decimals

Learning goal

“I can divide a decimal by a whole number by sharing a count of tenths or hundredths, keep the quotient's decimal point aligned with the dividend's, trade tenths for hundredths when I need to keep dividing - and use an estimate to prove the quotient is the right size.”

Dividend — the amount being divided or shared out. In 7.2 / 3, the dividend is 7.2.
Divisor — the number of equal shares (or the size of each share). In 7.2 / 3, the divisor is 3. In this unit the divisor is always a whole number.
Quotient — the answer to a division: the size of one equal share. In 7.2 / 3, the quotient is 2.4.
Place value — the value of a digit because of where it sits: ones, tenths, hundredths. Dividing is done place by place, and a leftover tenth can be traded for 10 hundredths.
Worked example

Divide 7.2 / 3. Step 1: Estimate first. 7.2 sits between 6 and 9 on the number line, so 7.2 / 3 sits between 6 / 3 = 2 and 9 / 3 = 3. The quotient must land between 2 and 3. Step 2: Rename by place value. 7.2 is 72 tenths (place-value chart: 7 ones = 70 tenths, plus 2 tenths). The dividend's point marks where the ones end - the quotient's point goes directly above it. Step 3: Share the count. 72 tenths / 3 = 24 tenths. Step 4: Rename back. 24 tenths = 2.4. Check against the estimate: 2.4 is between 2 and 3. Check by multiplying back: 2.4 x 3 = 7.2.

Check yourself — explain it

Why is 7.2 / 3 equal to 2.4 and not 24?

Paired problem — example still visible

Divide 8.4 / 4. -> 84 tenths / 4 = 21 tenths = 2.1

Faded completion — last step is yours

"9.6 / 3: estimate between 9 / 3 = 3 and 12 / 3 = 4. 96 tenths / 3 = 32 tenths, so 9.6 / 3 = ___" -> 3.2

Ready to practise?

10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.

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