Question

1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9+0+0

Answer 1

90

6+6=12

12+8=20

20+10=30

30+12=42

42+14=56

56+16+18=90

Answer 2

1+1+2+2+3+3+4+4+5+5+6+6+7+7+8+8+9+9+0+0 would equal to 90 if you break it down.

Hope this helps!

Have a great day :)