Missing Numbers in Subtraction to 100 Worksheets for 2nd Grade

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Grade 2MathAddition & SubtractionCCSS 2.NBT.B.5CCSS 2.OA.A.1

Skill: Finding the unknown whole or the unknown number taken away in two-digit subtraction equations

Preview of the Missing Numbers in Subtraction to 100 printable worksheet
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Teaching tips and what to try next

Ready for second graders who subtract two-digit numbers and can find a missing addend with sums to 100, as in Missing Addends Within 100. Ask children to label the whole and the two parts before solving, since mixing them up is the usual error. For more regrouping practice, try Two-Digit Subtraction 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)

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About this worksheet

Most subtraction pages ask for the answer at the end. A problem like ___ – 26 = 41 or 73 – ___ = 38 asks children to think about how the three numbers in a subtraction fact fit together. Second graders are expected to solve problems with unknowns in all positions and to subtract fluently within 100, and this second-grade worksheet gives practice with both.

The page has sixteen equations in two columns. Every equation subtracts a two-digit number from a two-digit number, and every answer is 10 or more. In about half of the equations the first number, the whole, is missing. In the rest, the number being taken away is missing. Some problems need regrouping and some do not, so children cannot work on autopilot. Each of the ten versions has new equations and its own answer key.

How to use it: teach two simple rules. If the first number is missing, add the two numbers you can see: for ___ – 26 = 41, add 26 + 41 to get 67. If the number being taken away is missing, subtract the answer from the first number: for 73 – ___ = 38, work out 73 – 38 = 35. A part-part-whole drawing, with the whole on top and the two parts below, makes the rules easy to see. Ask your child to check every answer by putting it in the blank and doing the subtraction.

The answer key gives every missing number. For smaller numbers, try our Missing Numbers in Subtraction Within 20 worksheet. For the addition side, try our Missing Addends Within 100 worksheet.