Mixed OperationsGrade 1Missing Number

Grade 1 Mixed Operations Missing Number

Grade 1 mixed operations missing number sheet: 24 problems on mixed addition and subtraction within 20, fact families.

CCSSAligned to Common Core 1.OA.6: Add and subtract within 20, demonstrating fluency for addition and subtraction within 10 using strategies such as making ten and decomposing.

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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. 1.
    ___ - 2 = 17
  2. 2.
    17 - ___ = 7
  3. 3.
    18 - 8 = ___
  4. 4.
    13 - ___ = 9
  5. 5.
    19 + 1 = ___
  6. 6.
    16 - ___ = 7
  7. 7.
    2 - 1 = ___
  8. 8.
    13 - ___ = 5
  9. 9.
    5 - 3 = ___
  10. 10.
    13 - ___ = 4
  11. 11.
    ___ - 18 = 1
  12. 12.
    9 - ___ = 8
  13. 13.
    19 - ___ = 2
  14. 14.
    15 - ___ = 7
  15. 15.
    ___ + 2 = 19
  16. 16.
    11 - ___ = 8
  17. 17.
    ___ - 3 = 12
  18. 18.
    15 - ___ = 9
  19. 19.
    2 + 9 = ___
  20. 20.
    9 - ___ = 2
  21. 21.
    6 - 5 = ___
  22. 22.
    10 - ___ = 3
  23. 23.
    18 - 3 = ___
  24. 24.
    6 - ___ = 4

What this worksheet covers

24 mixed operations problems fill this missing number page; problem 9 asks "5 - 3 = ___", and the sheet stays at that level throughout. 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 "___ - 3 = 12". Common Core 1.OA.6 is the slot this page fills.

Skills practised

The grade 1 mixed operations sequence covers addition and subtraction within 20 on the same page, and fact families; this page sits inside it. The skills on the page: mixed addition and subtraction within 20 and fact families. Working the page asks a student to reason backwards from a result to a missing part. Fourteen 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, "5 - 3 = ___" is one of them. A blank on a mixed page can belong to any operation, so the student has to reason about the relationship rather than recall a fact.

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 "19 - ___ = 2", Set B's is "19 + ___ = 20".

How to use this worksheet

Grade 1 attention runs short, so split these 24 mixed operations 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. Print Set B of this mixed operations missing number before writing on Set A; the same skill worked twice a week apart tells you far more than once.

One mistake to watch for

The operation sign is ignored: every problem on a mixed page is added. Problem 17 on this grade 1 missing number page, "___ - 3 = 12", is where to look for it.

Sign reading is not yet part of the routine because most practice pages only carry one operation.

Have the student circle or trace every operation sign before solving anything on the page.

The full guide to teaching mixed operationsTeaching mixed operations and order of operations: the grade 1–8 progression, why PEMDAS misleads, and how interleaved practice builds operation sense.

Other grade 1 mixed operations formats

The same skill in the other formats available at this grade.

  • DrillGrade 1 Mixed Addition and Subtraction to 20, 20 problems
  • Timed DrillGrade 1 Mixed Operations Timed Drill, 60 problems
  • Mixed ReviewGrade 1 Equal Groups: Repeated Addition to 20, 16 problems
  • Word ProblemsGrade 1 Sharing Equally, 12 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.

Missing Number sheets in other grade 1 topics

Six PDFs, no sign-up: three versions of this grade 1 mixed operations missing number and three answer keys, each 24 problems long.

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