Pairs That Make 100 Worksheets for 2nd Grade

Home › 2nd Grade › Math

Download PDF worksheetAnswer key (PDF)Worksheet + answer key (2 pages)

Prints on one US Letter page; the answer key is a separate page. Print at 100% / "Actual size" on US Letter paper. Free for personal and classroom use. Version 1 of 10. Choose another version.

Grade 2MathAddition & SubtractionCCSS 2.NBT.B.5

Skill: Finding the missing number that makes a total of 100

Preview of the Pairs That Make 100 printable worksheet
Page 1 preview (US Letter PDF)

Teaching tips and what to try next

Meant for second graders who know the pairs that make 10 and can count by tens from any number. A strip of a hundred chart cut into two pieces shows both parts at once and can be checked by putting it back together. Go further with Missing Addends Within 100 or practice the same thinking on paper in Two-Digit Addition With Regrouping.

10 versions, each with its own answer key

Same skill and layout, a fresh set of problems in every version, so children can keep practicing without repeating a page. Problems are not repeated between versions unless a skill has only a small number of possible problems (for example, the addition facts within 10).

Download all 10 versions (one PDF)All 10 answer keys (PDF)

Related worksheets

About this worksheet

Knowing which pairs of numbers make 100 is a big help for mental math in second grade and beyond. It works just like knowing the pairs that make 10, but with tens and ones together. This second-grade worksheet gives twenty equations where the total is always 100 and one of the two parts is missing.

Each equation looks like 37 + ___ = 100 or ___ + 45 = 100. The known part can be any number from 1 to 99, and the blank can come first or second. Numbers that end in 0 or 5 are quick warm-ups when they appear, while most problems need careful thinking about both the tens and the ones. Each of the ten versions has a new set of equations and its own answer key.

How to use it: start with the pairs of 10. If your child knows that 3 and 7 make 10, show that 30 and 70 make 100. Then try a number with ones, such as 64. One good strategy is to count up to the next ten, which is 6 more to 70, and then count by tens to 100, which is 30 more, so the answer is 36. Watch for a common mistake: children often make the tens add to 10 as well, and write 46 instead of 36. A quick check is to add the two parts and see if they really make 100.

The answer key shows every missing number. For more missing number practice, try our Missing Addends Within 100 worksheet. For adding with tens and ones, try our Two-Digit Addition With Regrouping worksheet.