Answer:
<h2>4 bilion = 4 × 10⁹</h2>
Step-by-step explanation:
The scientific notation:

where

4 billion:
in USA: 4,000,000,000
in Europe: 4 000 000 000 000

1) $375
500 *.25= 125
500-125= 375
2) (5/8)* 32= 20 girls in class
(3/8)* 32= 12 BOYS in class
4) 19+42+X=87
62+X= 87 (add 19 and 42 together )
X=25 ( subtract 87 from 62)
Answer:
c
Step-by-step explanation: