Guess & Check / trial & Improvement
Some problems can be solved by repeatedly guessing
answers and checking them until you have found a solution.
answers and checking them until you have found a solution.
guess
number of pigs 4 6 7 8 |
work out
number of ducks (12 heads) 8 6 5 4 |
work out
number of legs 4 x 4 + 2 x 6 = 26 6 x 4 + 6 x 2 = 36 7 x 4 + 5 x 2 = 38 8 x 4 + 4 x 2 = 40 |
check legs
26 < 40 too small - try more pigs 36 < 40 too small - try more pigs 38 < 40 too small - try more pigs 40 = 40 hurrah! |
So Nadia keeps 8 pigs
guess the
1st number 100 90 80 70 75 77 |
work out
2nd number 118 - 100 = 18 118 - 90 = 28 118 - 80 = 38 118 - 70 = 48 118 - 75 = 43 118 - 77 = 41 |
Subtract 100 - 18 = 82 90 - 28 = 62 80 - 38 = 42 70 - 48 = 22 75 - 43 = 32 77 - 41 = 36 |
Check for
36 needed x x x x x Hurrah |
So the two numbers are 77 & 4.
If you want some practice examples ask your teacher
if you can borrow a Thinkingcaps 1 booklet.
If you want some practice examples ask your teacher
if you can borrow a Thinkingcaps 1 booklet.