It's easiest to find numbers that add up to 10.
Try and add up 24 and 36 because you know that 6+4=10
so you get 6+4 and then do 20+30, add those together and you get 60
Then do the same for the other two numbers
8+2 and 40+20, add those together and you get 70
Add up 60 and 70 and you get 130 text messages.
