Foundations continued

The process is:

• Display the problem and say, ‘Here’s a new kind of problem. This number family has two letters – B and A. What letters?’ and signal.
• Say, ‘You cannot work a problem that has two letters. You need a number for one of the letters’, and add to show.
• Point to A = 10 and say, ‘Here’s a number for one of the letters. What letter?’ and signal.
• Say, ‘read the equation’, and signal. ‘A equals 10, so you can cross out A in the family and write what it equals. What does A equal?’ signal and add to show.
• Say, ‘Now you can work the problem because the family has only one letter. Remember, you can’t work a problem with two letters, but you can work a problem with one letter,’ Ask, ‘What’s the only letter in the family now?’ and signal.
• Ask, ‘Is B a small number or the big number?’ and signal. ‘Say the problem you work’, and signal. ’30 minus 10 equals 20. What’s 30 minus 10?’ and signal.
• Say, ‘We figured out what B equals. B equals 20, so I cross out B and write 20’, and add to show. Ask, ‘What are the small numbers in the family?’