He and his friends 83 + 1/6 write this amount as a decimal

Alright. the best way to do this is to make 1/6 into a decimal. you can do long division on paper, or on the calculator (if you wanna know how to do the long division let me know) but in the end we have 0.1666666 going on forever. I'll round to 0.1667. so we can say we have:

83 + 0.1667

we can also think of it like this:

83.0000
00.1667 +


all I did was add some zeroes where it didn't matter. no values changed. now we can just add like normal.

= 83.1667 hope that helps!