Line up the points, write zeros so every number has three places (4.2 becomes 4.200), then add or subtract as with whole numbers and bring the point straight down.
tenthsthe first place after the point
hundredthsthe second place after the point
thousandthsthe third place after the point
decimal pointthe dot between wholes and parts
Watch for: Lining up the last digits instead of the points. Subtracting 5.2 − 1.375 as 1.375 − 5.2 in the empty places. Forgetting the point in the answer.
At home: Compare race times or prices with three decimal places, like 12.345 seconds. Ask how much faster one is than the other.
Sample sheet and answer key
Luna's Space Adventure
Grade 4 · Adding decimals to thousandths · 4.CE.4
NameDate
Astronaut Luna is exploring a far-off corner of space. Solve each problem to help Luna's mission go smoothly!
Zeros fill the empty places, so the points line up. Add like whole numbers.
1
112.806+15.91128.717
2
118.400+6.19824.598
3
16.328+1.7508.078
4
18.300+17.49225.792
Subtract
Subtract like whole numbers, regrouping across the point. Bring the point down.
1
10.991−3.4067.585
2
13.876−10.7303.146
3
11.377−7.5003.877
4
6.994−2.7004.294
Story time
1
Gia swam a lap in 12.62 seconds, then in 11.016 seconds. How much faster was the second lap?
12.62 − 11.016 = 1.604
1.604seconds
Answer key
Something wrong with this sheet? A wrong answer, a hard-to-read picture? Report it
New problems every time, three levels (gentle, core and stretch), themes to pick from, a second page if you want one. Each sheet comes with an answer key and a one-page guide for grown-ups.
