What are the first 25 numbers added together?

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25 = 325

1 + 2 = 3

3 + 3 = 6

6 + 4 = 10

10 + 5 = 15

15 + 6 = 21

21 + 7 = 28

28 + 8 = 36

36 + 9 = 45

45 + 10 = 55

55 + 11 = 66

66 + 12 = 78

78 + 13 = 91

91 + 14 = 105

105 + 15 = 120

120 + 16 = 136

136 + 17 = 153

153 + 18 = 171

171 + 19 = 190

190 + 20 = 210

210 + 21 = 231

231 + 22 = 253

253 + 23 = 276

276 + 24 = 300

300 + 25 = 325

The first 25 numbers added together equal 325.