Watch the first slide and then try the next two yourself. Watch the fourth slide and then try the next three yourself. 1. Read the calculation. 2. Represent the top number in the place value chart. 3. Subtract - starting at the 1s column - cross off each one as you subtract it. 4. Repeat for the 10s. 5. Write your answer and check. ** If the bottom number is larger, regroup from the next column. One 10 = ten 1s. One 100 = ten 10s.