Find (5.3x10^3)-(8x10^2)

What are the measures of ∠a, ∠b, ∠c and ∠d? explain how to find each of the angle measure.

How many $20 bills do you need to have to make $280

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?