49
It is: 50*50*0+1 = 1
1 + 44 + 5 - 50 = 0
2099
4.9 + 1 = 5.9
1 100 + 50 + 90 + 45 _____ 285
209
53
76. 50 plus 27 is 77, and then subtract 1 (50-49) and you get 76.
50
50 plus 1
16 56 1
1+2 = 3 1+2+3 = 6 1+2+3+4 = 10 1+2+...+ N = 1/2(N+1)N if N = 50, 1+2+...+50 = 1/2 x 51 x 50 = 1275 Since 2+4+6+...+100 = 2 x (1+2+3+...+50) = 2 x 1275 = 2550