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Curriculum › Math ›Grade 2

Grade 2 Math · Level 4, Arithmetic within 100

Subtraction With a Missing Number

Find an unknown number in a subtraction equation using addition/subtraction relationships.

Questions like

  • 63 − __ = 28

How the lesson starts: Subtraction With a Missing Number

  1. Sammy's acorns

    Hello! Sammy the squirrel had 15 acorns. Whoosh! The wind blew some away. Now Sammy has 9. How many blew away? Let's help Sammy!

  2. Count up the gap

    Start at 9. Hop 1 to 10. Then hop 5 to 15. 1 + 5 = 6. So 6 acorns blew away! Check: 15 − 6 = 9.

  3. Count up again

    New day! Sammy had 13 acorns. Some fell in the pond. 7 are left. 13 − blank = 7. Count up from 7. Hop 3 to 10. Hop 3 to 13. 3 + 3 = 6. So 6 fell!