0:00
Decimal Multiplication
Select the skills to practice, and then click Go!
Foundational skills
Use related fact (int → dec)
\[ 6 \times 7 = 42 \rightarrow 0.6 \times 7 \]
Use integer fact to find decimal fact.
Use related fact (dec → int)
\[ 0.8 \times 5 = 4 \rightarrow 8 \times 5 \]
Use decimal fact to find integer fact.
Count decimal places in answer
\[ 2.5 \times 1.3 \text{ has } ? \text{ d.p.} \]
Determine d.p. in answer before calculating.
Estimate a decimal multiplication
\[ \text{Estimate } 3.2 \times 4.8 \]
Round and estimate the product.
Decimal × single digit
1dp × single digit (no carry)
\[ 1.2 \times 3 = \square \]
Multiply 1dp decimal by single digit.
1dp × single digit (with carry)
\[ 2.7 \times 4 = \square \]
Multiply with carrying required.
2dp × single digit
\[ 1.25 \times 4 = \square \]
Multiply 2dp decimal by single digit.
3dp × single digit
\[ 0.125 \times 8 = \square \]
Multiply 3dp decimal by single digit.
Decimal < 1 × single digit
\[ 0.4 \times 7 = \square \]
Multiply decimal less than 1.
Decimal × tens
Multiply by 20, 30, 40…
\[ 2.5 \times 20 = \square \]
Multiply decimal by multiple of 10.
Decimal × two-digit integer
1dp × two-digit integer
\[ 3.4 \times 12 = \square \]
Multiply 1dp decimal by two-digit integer.
2dp × two-digit integer
\[ 1.25 \times 16 = \square \]
Multiply 2dp decimal by two-digit integer.
Decimal × decimal (tenths)
Multiply two tenths
\[ 0.3 \times 0.4 = \square \]
Key skill: answer is 0.12, not 1.2!
Tenth × 1dp decimal
\[ 0.5 \times 1.2 = \square \]
Multiply tenth by 1dp decimal > 1.
Decimal × decimal (hundredths involved)
Tenth × hundredth
\[ 0.3 \times 0.04 = \square \]
Multiply a tenth by a hundredth.
Multiply two 2dp decimals
\[ 0.25 \times 0.4 = \square \]
At least one factor has 2dp.
Decimal × decimal (mixed)
Multiply two mixed decimals
\[ 1.5 \times 2.4 = \square \]
Both decimals greater than 1.
2dp × 1dp decimal
\[ 2.25 \times 0.4 = \square \]
Multiply 2dp by 1dp decimal.
Written methods
Set up decimal multiplication
\[ 3.45 \times 7 \text{ as integers} \]
Set up for column method.
Short multiplication
\[ 2.34 \times 6 \text{ (column)} \]
Use short multiplication method.
Long multiplication
\[ 1.25 \times 23 \text{ (column)} \]
Use long multiplication method.
Grid method
\[ 2.3 \times 14 \text{ (grid)} \]
Use grid/box method.
Integer and simplified answers
Decimal × integer = integer
\[ 2.5 \times 4 = \square \]
Answer is a whole number.
Simplified decimal answer
\[ 0.5 \times 0.2 = \square \]
Remove trailing zeros.
Comparing multiplication results
Which is larger?
\[ 0.6 \times 5 \text{ or } 0.5 \times 6 \text{?} \]
Compare two decimal products.
Order multiplications
\[ \text{Order: } 0.3\times4, 0.4\times4, 0.2\times5 \]
Put three products in order.
Special cases
Multiply by 0.1
\[ 4.5 \times 0.1 = \square \]
Same as dividing by 10.
Multiply by 0.01
\[ 3.5 \times 0.01 = \square \]
Same as dividing by 100.
Multiply by 0.5
\[ 7.6 \times 0.5 = \square \]
Same as halving.
Square a decimal
\[ 0.3^2 = \square \]
0.3² = 0.09, not 0.9!
Negative × positive decimal
\[ (-2.5) \times 4 = \square \]
Negative times positive.
Negative × negative decimal
\[ (-0.3) \times (-0.5) = \square \]
Two negatives give positive.
Timer (Optional)
0:00
Question