Lesson 5

Subtraction Facts Strategies

Est. Class Sessions: 2–3

Daily Practice and Problems

Teacher Notes
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TIMS Challenge

The solution above can also be found in the design on the turtle's back in the story Yu the Great. There are many solutions, but each solution has 5 in the center square. Challenge students to find more solutions. If students have difficulty, suggest that they put 5 in the middle.

T. Magic Square: Sum of 15

Complete the magic square using 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each row, column, and diagonal must have a sum of 15. This is the same magic square that Sun Feng had to do in the story Yu the Great.