MA 4.05Subtraction Strip Board and Charts

1. 1

   Problem 14 − 5: 'We start with fourteen.' Cover the numbers 15–18 with a plain wood strip.

2. 2

   Place blue strip 5 so it ends at the right edge of 14.

3. 3

   Read the last uncovered number to the left of the blue strip: 9. Write 14 − 5 = 9.

4. 4

   Do two more together.

5. 5

   The child works through subtraction tables, such as all facts starting from 10, and records them.

6. 6

   Check each answer with the subtraction control chart, or with Addition Chart 1 (9 + 5 = 14).

7. 7

   Introduce the working charts in the same order as the addition charts, ending with recall from memory.

What catches the child’s eye

• The plain wood strip covering the numbers past the starting number
• The blue strip pushed up against the edge of the starting number

Extensions, easiest to hardest

1. Write the related addition fact for each subtraction fact.
2. Fact families: 5 + 9, 9 + 5, 14 − 5, 14 − 9.
3. Recall subtraction slips without the board and check with the chart.