Many pairs of numbers can add up to 21, such as 10 and 11, 15 and 6, or 20 and 1. Additionally, you can use three or more numbers, like 7, 7, and 7, or 5, 8, and 8. The possibilities are numerous, depending on how many numbers you wish to include.
25
what two factors of -21 add up to -6
21, 21, 21, 21 , 15, 1
20 and 21
21
The numbers are 21, 22, 23, 24, and 25.
23
The numbers are -21 and -20.
341
41
21, 22, 23
21, 22, 23, 24