815
5298
The factors of 21 that add up to 8 are 1 and 7.
factors of 30 that add to 17 are 2 and 15
15 and 4 are the factors of 120 that add up to 19.
268
23
The interior angles of a regular hexagon add up to 720 degrees
-10 & -18
360
91
720.
They add up to 720 degrees.
The distinct prime factors of 550 are 2, 5 and 11. They add up to 18.
23
-273
27