The pattern is going like this: 40 + 6 = 46 + 8 = 54 + 10 = 64. They start by adding 6 and add 2 to the former number going forward. So the next number they would add would add 2 to is 10, which gives us 12. We can then add 12 to 64 to get out final number of 76. It would look like this when shown: 40 + 6 = 46 + 8 = 54 + 10 = 64 + 12 = 76
