Solve addition and subtraction problems by compensating with tidy numbers (including equal additions).
Numebr Framework Stage 6
Problem: “Work out 153 + 147.”
Record 153 + 147 on the board or modelling book. Show $153 and $147 with play money. Discuss the fact that transferring $3 gives $150 and $150, so the answer is obviously $300. Record the answer on the board or modelling book.
Problem: “To work out 79 + 79, Harry works out $80 + $80 with play money first and then says 79 + 79 must be 158.” Discuss Harry’s method. Record the answer on the board or modelling book.
Examples: Work out: 149 + 149 352 + 348 350 + 352 104 + 96 ...
Examples: Word stories and recording for: 440 + 439, 248 + 252, 349 + 350, 202 + 198 ...
Examples: Word stories and recording for: 150 + 149, 448 + 452, 147 + 153, 502 + 498, 1 009 + 991, 9 996 + 10 004 ...
Printed from https://meaningfulmaths.nt.edu.au/mmws/nz/resource/near-doubles at 12:05am on the 27th February 2024