Many numbers can be expressed as the sum of two or more consecutive integers. For example, 15=7+8 and 10=1+2+3+4. Can you say which numbers can be expressed in this way?
How many moves does it take to swap over some red and blue frogs? Do you have a method?
Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?