Apair of jeans is discounted for 30% off. if the original price is $31.50,what is the discount amount that will be taken off of the original price?

You simply multiply the discount by the original price (remember to change the percent to a decimal).
0.30*31.50=9.45
So, the discount took $9.45 off of the original price.

As June21 explained, you can turn 30% into a decimal by dividing 100 into 30,(30/100), then multiply the $31.50 with 0.3 to get the amount after taken off the original price.

0.3*31.50=9.45.