In this activity the purpose is to find out how many tens and ones blocks are hidden from a given total.
solve subtraction problems
- Show the students you have put blocks on the OHP to represent a number but some of them are hiding (covered). Ask them to work out how many are hiding.
All my blocks together show 78, but some of them are hiding.
How many are hiding?
- After a time for thinking, have students share their answers and their thinking, recording some of these on the board.
- Uncover the hiding blocks, and count them to show students both the number hiding and the total number.
- Repeat the activity with a different number of blocks hidden.