A television normally sells for $320. This week, it's on sale at 60% off the normal price. What is the sale price?

if it is 60% off, then u r actually paying 40%
so ur paying 40% of 320....turn ur percent to a decimal..." of " means multiply

so the sale price is : 0.40(320) = $ 128 <==

or u could also do it this way...
320 - 0.60(320) = 320 - 192 = $ 128 <==