Question 267907
Hello, 
Let's set it up this way. Let "p" be the price of the calculator. Then we can write this equation. 
p+(6% times p)=$137.80 Rewritten it looks like this:
p+.o6p=137.8 Combine like terms to get:
1.06p=137.8 Divide both sides by 1.06 to get:
p=130
Now we know the calculator cost $130 but check it out for yourself to see when you multiply 130 time 6%. You should get what the tax is, right?
RJ
There is a book on the basics of math you might check out> 
www.math-unlock.com