1st Grade Find the Unknown Worksheets
50 printable 1st Grade math worksheets on Find the Unknown. Every sheet has a worked answer key — 50 in all. The first three worksheets are free to download; All Access opens the rest and every answer key.
In Grade 1: addition and subtraction fact families within 20, with the missing number in any place.
Practice pages support a program; they are not the lesson. These sheets reinforce Building Number Sense Grade 1, the sequenced K–5 math series from Faith Thinkers. See every program →
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3 of 50 worksheets free · All Access opens the other 47 and all 50 answer keys
The free sheets download from this page as PDFs. Open to everyone.
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All 50 worksheets in this set
Find The Unknown Practice, numbered 1 to 50. The free ones open as PDFs.
Teaching Find the Unknown
What it is
Fact families within 20 with the blank in any place: a missing addend, a missing total, or the number something was taken from. A story problem asks how many there were at first.
When a child is ready
Ready once addition and subtraction facts within 10 are quick.
If they struggle
Ask whether the blank is the whole or a part. A missing part is found by subtracting; a missing whole is found by adding.
Worksheet preview
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