6A

Adding and subtracting decimals

Adding and subtracting decimals by lining up the decimal points, with estimation to check answers.

Line up the decimal points

Example 1●

Find $12.7 + 3.85$.

$12.70 + 3.85$

$= 16.55$

Example 2●●

Find $20 - 7.36$.

$20.00 - 7.36$, borrowing across the zeros.

$= 12.64$. Check: $12.64 + 7.36 = 20$.

Flashcards

Adding decimals

Line up the decimal points; pad with zeros.

$5 - 1.25$

$3.75$

Check a subtraction

Add the answer back.

Practice

Find $12.7 + 3.85$.
Find $20 - 7.36$.
Find $5 - 1.25$.
Find $4.35 + 5.75$.
Find $0.4 - 0.31$.
Find $1.2 + 3.45 + 3$.
You pay for a $\$6.55$ lunch with a $\$20$ note. How much change?
A plank is $3.2$ m. You cut off $0.85$ m. How long is the rest, in metres?

More questions

New numbers every time. Keep going until you get five in a row.