Grade 1 Subtraction Missing Number
Grade 1 subtraction missing number sheet: 24 problems on subtraction within 20, unknown-addend facts.
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Three different problem sets — same skill, same layout, fresh numbers.
Preview — Set A
Find the number that belongs in each blank.
- 1.15 - ___ = 14
- 2.16 + ___ = 18
- 3.16 - ___ = 5
- 4.1 + ___ = 19
- 5.6 - 4 = ___
- 6.1 + ___ = 15
- 7.___ - 1 = 2
- 8.8 + ___ = 14
- 9.6 - ___ = 3
- 10.5 + ___ = 8
- 11.8 - 4 = ___
- 12.5 + ___ = 15
- 13.___ - 1 = 1
- 14.7 + ___ = 18
- 15.___ - 8 = 7
- 16.1 + ___ = 12
- 17.9 - ___ = 2
- 18.2 + ___ = 10
- 19.15 - 4 = ___
- 20.10 + ___ = 11
- 21.13 - 4 = ___
- 22.10 + ___ = 14
- 23.___ - 3 = 3
- 24.9 + ___ = 18
What this worksheet covers
24 subtraction problems fill this missing number page; problem 9 asks "6 - ___ = 3", and the sheet stays at that level throughout. Within that, the blank moves between positions from problem to problem, so no single procedure clears the page and the numbers run as high as 19. Further down, problem 17 asks "9 - ___ = 2". Common Core 1.OA.6 is the slot this page fills.
Skills practised
The grade 1 subtraction sequence covers facts within 20, unknown-addend equations, and subtracting multiples of ten; this page sits inside it. What a student is asked to do here is subtraction within 20 and unknown-addend facts. Concretely, the sheet tests whether a student can reason backwards from a result to a missing part. Thirteen different answers appear across the 24 problems, so a student cannot copy one result down the page.
About the missing number format
The 24 problems here move the unknown around, so a student solves for a missing part as often as for a result; problem 9, "6 - ___ = 3" is one of them. Blanks in the minuend or subtrahend force the student to think of subtraction as a missing part, which is the idea behind every later inverse operation.
Set A, Set B and Set C
The three sets come from the same generator with three different seeds: same skill, same layout, fresh numbers, and an answer key computed with the problems. Where Set A's problem 13 is "___ - 1 = 1", Set B's is "20 - ___ = 15".
How to use this worksheet
Grade 1 attention runs short, so split these 24 subtraction problems over two or three sittings rather than pushing through in one; a number line or counters within reach is a strategy, not a failure. Ask the student to re-work one missed subtraction problem from scratch on Set B rather than correcting it in place; the second attempt shows whether the method changed.
One mistake to watch for
Subtraction facts are recomputed by counting back one at a time. Watch problem 17 of this missing number — "9 - ___ = 2" — for this one.
The relationship to addition has not been made explicit, so 13 − 8 is not being read as "8 plus what is 13".
Practise fact families as a unit, four equations at a time, and give unknown-addend problems alongside the subtraction ones.
Other grade 1 subtraction formats
The same skill in the other formats available at this grade.
- Drill — Subtracting Multiples of 10 — Grade 1 Practice, 22 problems
- Timed Drill — Grade 1 Subtraction Timed Drill, 60 problems
- Mixed Review — Grade 1 Subtraction Mixed Review, 24 problems
- Word Problems — Grade 1 Addition and Subtraction Word Problems, 12 problems
- Vertical Format — Grade 1 Subtraction Vertical Format, 20 problems
A step either side
The same format one grade down and one grade up — the easier sheet is often the faster fix when this one is not landing.
- Kindergarten Subtraction Missing Number — kindergarten, 20 problems
- Grade 2 Subtraction Missing Number — grade 2, 24 problems
Missing Number sheets in other grade 1 topics
Six PDFs, no sign-up: three versions of this grade 1 subtraction missing number and three answer keys, each 24 problems long.