Sunday, February 7, 2016

Abacus Lesson 25: Subtraction: Complementary Numbers Respect to 10'S Column

AbacusVideo: Lesson 25: Subtraction: Complementary Numbers Respect to 10'S Column

10 - 7 (10 subtract 7)
In the 1's column, complement of 7 is 3, add 3 in 1s column, take away 1 in the 10's column
Answer is 3

10 - 6 (10 subtract 6)
In the 1's column, complement of 6 is 4, add 4 in the 1's column, subtract 1 in 10's column
Answer is 4

11 - 8 (11 minus 8)
In the 1's column, complement is 2, add 2 in 1's column, add 1 in 10's column
Answer is 3

12 - 9 (12 minus 9)
In the 1's column, complement of 9 is 1, add 1 in 1's column, take away 1 in 10's column
Answer is 3

17 - 9 (17 minus 9)
In the 1's column, complement of 9 is 1, add 1 in the 1's column, take away 1 in 10's column
Answer is 8

12 - 8 (12 minus 8)
In the 1's column, complement of 8 is 2, add 2 in 1's column, take away 1 in 10's column
Answer is 4

Video: Abacus Lesson 25: Subtraction: Complementary Numbers Respect to 10'S Column


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