Grade 6 Adding Multi-Digit Decimals
Grade 6 decimal addition out to the thousandths place using the standard algorithm. Sixteen problems with a complete answer key, free to print.
Add the decimals using the standard algorithm. Line up the decimal points.
- 1.51.366 + 33.324 =
- 2.52.481 + 71.039 =
- 3.64.644 + 98.271 =
- 4.88.048 + 5.426 =
- 5.21.285 + 65.226 =
- 6.73.864 + 91.162 =
- 7.39.458 + 79.942 =
- 8.3.861 + 48.023 =
- 9.49.188 + 83.607 =
- 10.45.608 + 58.543 =
- 11.51.291 + 73.553 =
- 12.60.441 + 21.068 =
- 13.43.453 + 8.341 =
- 14.61.665 + 90.375 =
- 15.50.603 + 8.397 =
- 16.61.136 + 66.223 =
What this worksheet covers
There are sixteen addition problems here, on one printable page, with the worked answer key on the second. Within that, the operands run to as many as three decimal places, so the decimal points have to be lined up rather than the right-hand digits; numbers reach 98.271. Grade 6, The Number System, Common Core 6.NS.3: that is the exact slot this page fills.
Skills practiced
At this point in the sequence, work in addition is really about decimals and fractions with unlike denominators. Concretely, the page tests whether a student can keep decimal points aligned rather than right-aligning digits out of habit. The useful question after marking is not how many were right but whether the same method produced all of them.
How to use this worksheet
Check in the middle, not just at the end. Catching a systematic slip at problem four saves re-teaching the whole page, and this sheet is long enough for a wrong method to get well practised before anyone notices. Mark it the same day using the key on page two — an error caught immediately is a correction, and one caught next week is a habit.
One mistake to watch for
Decimals aligned to the right: 3.5 + 0.42 = 3.92.
The right-alignment habit from whole-number addition is being applied to a notation where position, not the right edge, determines value.
Have the student write in the missing placeholder zero (3.50) before adding. Aligning the decimal points then aligns everything else automatically.
Related worksheets
Also aligned to 6.NS.3
Other sheets covering 6.NS.3. Same target, different problems, so a student who has seen this page has not seen these.
- Grade 6 Subtracting Multi-Digit Decimals — grade 6, 16 problems
A step either side
The same topic one grade down and one grade up — the easier sheet is often the faster fix when this one is not landing.
- Grade 5 Adding Decimals to Hundredths — grade 5, 18 problems
- Grade 7 Adding Rational Numbers — grade 7, 20 problems
One PDF, sixteen problems, and a full key: this is grade 6 addition practice for decimals and fractions with unlike denominators, free for home and classroom use.