Subtraction, missing numberUp to 20
Name: Date:
120 − = 0
2 − 2 = 10
320 − = 13
49 − = 1
516 − = 8
6 − 16 = 3
7 − 18 = 2
85 − = 5
9 − 1 = 0
1013 − = 11
Missing number subtraction worksheets
These free printable worksheets blank out one number in a subtraction sentence within twenty — sometimes the number you start with, sometimes the number taken away — so a child has to reason about the whole relationship instead of following a procedure.
Kid stuck on one? You don’t just get the sheet.
Missing number subtraction
The answer key prints on a separate page.
What's on this sheet
The two blanks are genuinely different problems. Finding the missing subtrahend in 15 − __ = 8 is a counting-up question: how far from 8 up to 15? Finding the missing minuend in __ − 6 = 9 runs the other way and is solved by adding. A child who has met both stops treating the minus sign as an instruction to always subtract whatever they can see.
Why this sheet works
This is where subtraction as difference finally earns its keep. Counting up from the smaller number is usually faster and less error-prone than counting back, and a page of gaps makes that strategy the obvious one to reach for. Children who only meet take-away problems rarely discover it on their own.
How this one works
One question from this sheet, worked through a step at a time.
20 − 20
20−20
20→20=0
20−20=0
- 20 − 20. These two are close together, and that changes what is worth doing: taking 20 away a place at a time would need a borrow, and the gap between them is only 0.
- So count UP from 20 instead: 20 up to 20 is 0, in one hop.
- That gap IS the answer: 20 − 20 = 0.