Can someone me with this math problem pls? how would i show my work in this question?

(3 * 10^9)= 3 * 1,000,000,000 = 3,000,000,000

(5*10^6)= 5 * 1,000,000= 5,000,000

5,000,000* 3,000,000,000 = 1.5*10^16

1.5 is the beginning of your zeros and 10^16 is the zeros after the number

whatever you can spend with $11.53 or under.

step-by-step explanation:

20 - 8.47 = 11.53. take away the money he used for lunch from the starting amount of 20.

8 2/3 is the answer

step-by-step explanation: just use a calculator