Adding Decimals
Decimals practice
Add numbers with up to two decimal places, including regrouping and whole numbers.
Decimals practice
Add numbers with up to two decimal places, including regrouping and whole numbers.
Add two decimals and type the exact sum.
The numbers have up to two decimal places. Some questions use different numbers of decimal places, like 3.8 + 2.65, and some include a whole number, like 3 + 0.47. A sum can be 10 or more. A zero at the end does not change a value, so 4.5 and 4.50 are the same answer.
Typical level: Grade 5In the U.S. Common Core, Grade 5 adds decimals to hundredths. Curriculum timing varies.
Tenths add to tenths and hundredths add to hundredths, so the decimal points line up. Do not line up the last digits: that would add 8 tenths to 5 hundredths. Add from right to left. When a column makes 10 or more, write its ones digit and regroup 10 of that place as 1 of the next place to the left.
If naming the places is the hard part, start with Decimal Place Value.
Example: 3.8 + 2.65
3.8 plus 2.65 is 6.45, written as a column problem with the decimal points lined up. 3.8 is written as 3.80. A zero added at the end does not change its value. The tenths column makes 14 tenths, so 1 is regrouped into the ones column.
Zeros added at the end do not change the value.
The small 1 above a column is the regrouped 1.
A whole number has empty places too. In 3 + 0.47, write 3 as 3.00. The sum is 3.47.
0.67 plus 0.45 is 1.12, written as a column problem with the decimal points lined up. The tenths column makes 11 tenths, so 1 is regrouped into the ones column. The hundredths column makes 12 hundredths, so 1 is regrouped into the tenths column.
The small 1 above a column is the regrouped 1.
0.67 + 0.45
Hundredths: 7 + 5 = 12, write 2, regroup 1 tenth
Tenths: 6 + 4 + 1 = 11, write 1, regroup 1 one
Ones: 0 + 0 + 1 = 1
0.67 + 0.45 = 1.12
10 hundredths make 1 tenth, and 10 tenths make 1 one, so a regroup crosses the decimal point. Two numbers below 1 can have a sum above 1.