Answer |
37
The rule is to replace + – with –. Thus 56 – 19 = 37.
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Answer |
3 in 4. The possible combinations of drawing the balls are
odd – odd
odd – even
even – odd
even – even
There is only one of these combinations where an odd
numbered ball is not drawn out. The chance of drawing at
least one odd-numbered ball is therefore three in four.
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Answer |
20. add 1, 1, 2, 2, 3, 3, 4, 4.
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Answer |
32. The next cube number below 64 (4 × 4 × 4) is 27 (3 × 3 × 3). In order to construct a solid cube, therefore, with none left over, 59 – 27 = 32 blocks need to be taken away. |
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