since that the first is 14+19 and they are just adding 4+9 which is 13 so, the last is just a 3, and 1+1 is 2, plus the 1 that we have from the 13, then, you just add 1 on the Middle.
With 25+13 also you add normally, just add a 2 on the middle. And With the 3rd one add a 3 on the middle. So, with the last one, you add a 4 too.
