Answer:
See attached.
Explanation:
10×, 100× (multiplication)
As the example in your problem statement shows, moving the decimal point in the operands of the expression can have the effect of multiplying the result by some power of 10. Your example shows multiplication by a factor that is 1/10 of the original, so the product will be 1/10 of the original.
The next line asks for an expression that will give a product 1/100 of the original value. That can be obtained by multiplying both operands (in the multiplication problem) by 1/10 of their original value. That is ...
... (a/10)·(b/10) = (ab)/100
10× (division)
In a division problem, too, adjusting the position of the decimal point in the operands will adjust the position of the decimal point in the quotient.
In particular, making the divisor a factor of 10 smaller means the quotient will be a factor of 10 larger. (Something can be divided into more pieces when the pieces are smaller.) We want the quotient to be 10× as large, so we can choose the expression with the divisor that is 1/10 its original value. 12/10 = 1.2
Using variables to show this as we did above, ...
... a/(b/10) = a·(10/b) = (a/b)·10