Here we have a maths investigation on addition, suitable for year 2. There are four numbers shown. The task is to choose any three numbers and add them up. Each number can be used up to 3 times, but the total sum must not include more than 3 numbers. So the sum could be 2 + 2 + 2, or 2 + 4 + 4 etc. How many different ways are there of doing this and how many different answers are there? Usually children begin in a haphazard way, but it is important that they try to develop logical systems to make sure that all possibilities have been covered. Addition: How many sums?