Answer:
10
Step-by-step explanation:
20 divided by 4 = 5 and times it from there
 
        
             
        
        
        
Answer:
Step-by-step explanation:
-1760 is the answer 83 times 83 minus 93 times 93 is -1760
 
        
             
        
        
        
Take the original price, multiply it by 20% (you have to move the decimal place two to the left, so it becomes .2), then subtract the answer from the original price. 
39.99*.2= $7.998
39.99-7.998= $31.99
If you wanted to, you could also round the $7.998 to $8.00. Your answer would be the same. 
        
             
        
        
        
He got 4 percent right. 16 percent of 15 is 4 :)