Question

1+2+3+4+....+15 CALCULCULATI

Answer 1

1 +2+3+4+...+15 =
n = ( 15 - 1 ) : ( 2 - 1 ) +1 =
n = 14 : 1 +1
n = 14 +1
n = 15

S = [( 15 +1) x 15] : 2 =
S = ( 16 x 15 ) : 2
S = 240 : 2
S = 120.

Answer 2

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15=120