Question 1073261
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1+1+2÷2+1+2+3÷3+1+2+3+4÷4....

Separate it into groups to get the pattern

1 + 1+2÷2 + 1+2+3÷3 + 1+2+3+4÷4....

Extend the pattern until there are 20 numbers
(we get the 20th number just as it bwgins the 
last group):

1 + 1+2÷2 + 1+2+3÷3 + 1+2+3+4÷4 + 1+2+3+4+5÷5 + 1

We do divisions first, and they're all 1's: 

1 +  1+1  +  1+2+1  +  1+2+3+1  +  1+2+3+4+1  + 1

1 +   2   +    4    +     7     +     11      + 1

Answer: 26 

Edwin</pre>