Answer :
1+4=5
2+5=7
5+7=12
3+6=9
12+9=21
I do not see21 up here so please cheek your question again or please change the 19 to a 21
1+4=5
2+5=7
5+7=12
3+6=9
12+9=21
I do not see21 up here so please cheek your question again or please change the 19 to a 21