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- Subtract the bottom number from the top number. Imagine the top
- number as piles of coins. Click in each column of coins to remove a coin.
- When you have finished click on the FINISHED button to see if you are
- right. If you are wrong click on the RESTART button to restart the
- same problem or the NEXT ONE button to select the next problem. When
- you are done click on the EXIT button to return to the main menu.
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- Problems arise when you do not have enough coins in a pile to take-
- away. You can then click on CHANGE 10 to change a 10 into 10 ones; or
- CHANGE 100 to change a 100 into 10 tens.
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- Many people struggle with 'rules' which only confuse matters.
- By thinking of a number as coins you can see what is going on. If we
- had 123-5 we could imagine it as £1.23 - £0.05 We do not have enough
- pennies to take so we change a ten into pennies.
- WE STILL HAVE £1.23. (1 Hundred, 1 Ten, 13 Ones)
- We have not taken anything away or added anything on. We only changed
- the way it looks. Click to take away the 5 pennies and we get £1.18.
- Click on FINISHED and the answer is confirmed as 118. NEXT ONE...
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