If you pair up the numbers 1 and 100, 2 and 99, 3 and 98, 4 and 97, and so on until you reach 50 and 51, you will have 50 pairs of numbers.
1 + 100 = 101
2 + 99 = 101
3 + 98 = 101
…
49 + 52 = 101
50 + 51 = 101
You will then have 50 pairs of numbers that each add up to 101.
Therefore, you have 101 added to itself 50 times, which can be calculated by
50 * 101 = 5050
Hope this helps! :)
