2. Blue strips 1 to 9 with numerals at the end.
3. Red strips 1 to 9 with numerals at the end. The red strips are divided into sections such as 3 squares for the 3 strips.
4. Brown wooden strips the same length and size as the red and blue strips but without numerals or lines.
Or
5. A narrow board with a row of numerals 1 to 18, one wooden strip the length of the 1 to 18 and blue and red strips as above.
2. Select a problem such as 15 - 9=,
3. Select a brown strip to cover all the numerals on the right except 15.
4. Place the 9 blue strip at the end of the brown strip.
5. Notice the spaces left. This is the answer.
6. Now do 15 - 8, 15 - 7, 15 - 6. At this point you will have reached the blue line.
7. Now it is necessary to subtract in two categories. Therefore, 15-4 is 6 units minus 4 units and 1 ten minus 0 tens.
8. Put in the red strip. This is the answer.
2. Lay out the brown strip to cover all but the first 9 spaces.
3. Place the blue 9 strip next to the brown strip. The answer is 0.
4. Find the answer to 9 - 8 by placing the brown strip to cover all but 9 spaces.
5. Place the blue strip for 8 at the end of the brown strip.
6. One space is left. Thus, the answer is 1.
2. Verification of teacher.
2. Seeing the problem represented in strips.
3. Writing the answer on paper.
4. Verifying the answer on the control chart.
2. To know subtraction combinations.
3. Memorization of subtraction facts.