Perplexing problems 1. What’s the number?  It has 3 digits  It is a multiple of 11  All the digits are odd  The sum of its digits is a square number Answer: 979

Perplexing problems 2. How many go by bus?  In a school of 1200 pupils, 580 are girls.  One third of the pupils travel to school by bus  462 boys do not go by bus  How many girls do go by bus? Answer: 242

Perplexing problems 3. How many altogether?  Sam and Ben collect marbles  Sam tells Ben, “If you give me 5 marbles I’ll have twice as many as you.”  Ben says, “If you give me 4 we would have the same number”.  How many marbles were there altogether? Answer: 54

Perplexing problems 4. What number was the middle house?  Five houses next door to each other were on the odd side of the road.  They were all 2-digit numbers, and in ascending order  The fourth one was the only prime number  What number was the middle house? Answer: 95

Perplexing problems 5. How much altogether?  Ann, Bob and Carol are counting their money  Ann and Bob together have £5.98  Bob and Carol together have £6.47  Ann and Carol together have £8.51  How much do they have altogether? Answer: £10.48