Start out by making sure you understand the problem by doing a simpler version, such as adding up the first 5 numbers. To add up the numbers 1 + 2 + 3 + 4 + 5, you would start by adding 1 + 2 to give you 3, then add 3 to give you 6, then add 4 to give you 10, and 5 to give you 15. The intermediate numbers we kept track of are called running totals. 3, 6, 10, and 15 were all running totals. The 15 is also the final sum of all the numbers. Now write out the running totals and final sum of the first 10 numbers, e.g., 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10.