Reasoning#1

Solve it If you Can?
1. 11=20
2. 12=31
3. 13=42
4. 14=53
Then 18=?
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Sol.:- 1. 11=20,  1+1=2, 1-1=0  so 20
          2. 12=31, 1+2=3, 2-1=1 so 31
          3. 13=42, 1+3=4, 3-1=2 so 42
          4. 14=53, 1+4=5, 4-1=3 so 53
           similarly in 18, 1+8=9, 8-1=7 so 18=97