All you have to do is addition. 2+5+4=11. Or you can break it down and go 2+5=7 and then 7+4=11. Or 5+4=9 then 9+2=11. Or 4+2=6 then 6+5=11.
U call it keep change change. keep 15.7. change it to subtract and change -3.45 to just 3.45 (positive not negative)
Let x the age of John
Amy's age = x + 9
from question, we get,
John's age + Amy's age = 23
x+(x+9)= 23
=> x + x + 9 = 23
=> 2x = 23 - 9
=> x = 14/2
=> x = 7
32. 15.99 x .40 = 6.40
15.99 - 6.40 = 9.59
80/ 9.59 = 8.34
Jenny can buy A. 8 CD’s with her $80
31. 5,000 x .10 = 500
5,000 - 500 = 4,500
4,500 x .15 = 675
4,500 + 675 = 5,175
Ben will earn C. $5,175 after one year one the job