What is 81 over 10 times 10 over 42

I am assuming by "over" you mean divide.

81/10=8.1
8.1/10=.81
.81/42=0.0192857142857143

Hope that helps

Let's break it down 81/10 =8.1. If you multiply 8.1 by 10 it's equal to 81, again. If you divide 81 by 42, you get *drum roll* 1.92 - not a nice even number - but that'd be your final answer. ((: I hope all is well, and I helped! Good luck, rockstar! Or if you're cross multiplying you have to do - 81/10 * 10/42 If you multiply 81 by 42, you get 3,402 Then 10 by 10 is a simple 100. So you have 3,402 and 100. (: