Trade First Subtraction

TRADE-FIRST SUBTRACTION WITH 2 DIGIT NUMBERS

By: Mrs. Vaitkevicius

2nd Grade Teacher

Crescentwood Elementary

BASE 10 BLOCKS

Numbers in the 10’s place are represented by longs.

Numbers in the 1’s place are represented by cubes.

10 cubes = 1 long.

This long is the same as writing the number 10.

This cube is the same as writing the number 1.

The 2 digit number

4 3 has:

4 longs = 40 + 3 cubes = 3

40 + 3 = 43

43 – 27 = ?

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4 3

- 2 7

?

BORROW FROM MY NEIGHBOR

4 3

BORROW FROM MY NEIGHBOR

4 3

BORROW FROM MY NEIGHBOR

4 3

43 – 27 = ?

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34 3

- 2 7

43 – 27 = ?

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3 134 3

- 2 76

43 – 27 = ?

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3 134 3

- 2 71 6

43 – 27 = 16

References/Acknowledgments

Bell, Max, Project, University, & Bell, Max. (2004). Everyday

Mathematics 2 grade teacher. 2004-01-01.

Michigan Department of Education. (2006). Mathematics Second

Grade Content Expectations. Retrieved February 10, 2010, from

http://www.michigan.gov/documents/Math_02_87402_7.pdf