The regular price of a calculator is 15.40 it goes on sale for 30% what is the amount of savings

30% of $15.40 is (0.3 x $15.40) = $4.62.

From the way the question is written, we don't know if

that $4.62 is the discount or the sale price.

Is the calculator on sale for 30%?

Or is it on sale for 30% OFF?

If 30% is the discount, then the amount of saving is $4.62.

If 30% is the sale price, then the amount of saving is ($15.40 - $4.62)

= $10.78.