Multiply it by the 1st ten odd numbers: 1*25 = 25, 3*25 = 75, 5*25 = 125 .... etc
25, 50, 75, 100, 125, 150, 175, 200, 225, 250
5, 10, 15, 20, 25, 30, 35, 40, 45, 50.
5, 10, 15, 20, 25, 30, 35, 40, 45, 50.
5, 10, 15, 20, 25, 30, 35, 40, 45, 50. There you go
25 and 50
The sum of the first 25 numbers is 25*26/2 = 325 So the sum of the first 25 multiples of 12 is 325*12 = 3900
30, 60, 90, 120, 150
It is 75.
25, 50, 75, 100
The first four multiples of five: 5, 10, 15, 20
975
75