## Numbers Puzzles

57. What is the value of 56 + –19?
Answer
 37 The rule is to replace + – with –. Thus 56 – 19 = 37.
58. You have two bags each containing six balls. The first bag contains balls numbered 1 to 6 and the second bag contains balls numbered 7 to 12. A ball is drawn out of bag one and another ball is drawn out of bag two. What are the chances that at least one of the balls drawn out is an odd numbered ball?
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.
59. 0, 1, 2, 4, 6, 9, 12, 16, ? What number should replace the question mark?
Answer
 20. add 1, 1, 2, 2, 3, 3, 4, 4.
60. You have 59 cubic blocks. What is the minimum number that needs to be taken away in order to construct a solid cube with none left over?
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.