Operations with Decimals: Practice

Line up the decimal points. Both numbers have a single digit in the tenths place, so add those digits.

$0.3 + 0.4 = 0.7$

Three tenths plus four tenths is seven tenths.

Ignore the point and multiply as whole numbers: $2 \times 3 = 6$. The factor $0.2$ has one decimal place and $3$ has none, so the product has $1 + 0 = 1$ place.

$0.2 \times 3 = 0.6$

Multiply as whole numbers: $5 \times 2 = 10$. The factor $0.5$ has one decimal place and $2$ has none, so the product has one place.

$0.5 \times 2 = 1.0 = 1$

Half taken twice makes one whole.

Multiplying by $10$ makes every digit worth ten times as much, which slides the decimal point one place to the right.

$2.5 \times 10 = 25$

The divisor $4$ is a whole number, so divide directly and bring the point straight up. Four goes into $4$ ones once and into $8$ tenths twice.

$4.8 \div 4 = 1.2$

Pad $0.5$ to two decimal places so the columns line up: $0.5 = 0.50$. Then add with the points aligned.

$0.25 + 0.50 = 0.75$

Line up the points. You cannot take four tenths from zero tenths, so borrow the whole as ten tenths.

$1.0 - 0.4 = 0.6$

Ten tenths minus four tenths is six tenths.

Multiplying by $10$ slides the decimal point one place to the right, moving the $7$ from the tenths place into the ones place.

$0.7 \times 10 = 7$

Multiply as whole numbers: $11 \times 2 = 22$. The factor $1.1$ has one decimal place and $2$ has none, so the product has one place.

$1.1 \times 2 = 2.2$

Line up the points and subtract the tenths, since each number has a single tenths digit.

$0.9 - 0.3 = 0.6$

Dividing by $10$ slides the decimal point one place to the left.

$1.5 \div 10 = 0.15$

The ones digit becomes a tenths digit and the tenths digit becomes a hundredths digit.

Multiply as whole numbers: $3 \times 2 = 6$. The factor $0.3$ has one decimal place and $2$ has none, so the product has one place.

$0.3 \times 2 = 0.6$