Missing Number Worksheets
Free printable missing number worksheets. Two-digit addition and subtraction written with a blank, like 34 + __ = 61 and __ - 18 = 25.
Twenty two-digit problems a sheet, addition and subtraction mixed, each with one number replaced by a box: 34 + ___ = 61, or ___ - 18 = 25. The blank moves between the two operands, never the answer - a sheet that hid the answer would just be an ordinary worksheet.
At two digits the missing number is no longer something to count to, so it forces the actual relationship: to find the box in 34 + ___ = 61 you subtract, and to find it in ___ - 18 = 25 you add. Working out which operation undoes the one on the page is the skill these build.
What this worksheet covers
- Find a missing number in a two-digit addition or subtraction equation
- Choose the inverse operation that reveals the blank
Common Core standards
- 2.NBT.B.5 Fluently add and subtract within 100 using place-value strategies.
Frequently asked questions
What is a missing number problem?
An equation with one value replaced by a blank - 34 + ___ = 61. Solving it means running the arithmetic backwards, which is a different skill from working an ordinary problem left to right.
Which number is left blank?
One of the two operands, chosen so the sheet alternates. The answer is never the blank; that would just be the standard worksheet.
What grade is this for?
Second and third grade, once two-digit addition and subtraction with regrouping are steady and the inverse relationship is being made explicit.
How do you find the missing number?
Use the opposite operation. For 34 + ___ = 61, subtract: 61 - 34 = 27. For ___ - 18 = 25, add: 25 + 18 = 43. The one to watch is 61 - ___ = 34, where you subtract again: 61 - 34 = 27.