Answer:
400
Step-by-step explanation:
800-400=400
This is only my opinion. I could be wrong.
My guess is:
Somebody else used that book before you, maybe last year or
the year before, and it was somebody who didn't mind writing
in his book.
One day he didn't have time to write down the homework in his
assignment notebook, so he just circled the homework problems
in his textbook.
Salutations!
<span>The ratio of boys to girls in a school is 5:4. if there are 180 students, how many girls are there?
Let the number of girls and boys be 'x'.
</span>

<span>
Add 5 and 4
</span>

<span>
</span>

<span>
Now, multiply the ratios by 20.
Boys =
20 </span>× 5 = 100
Girls = 20 × 4 = 80.
There were 80 girls.
Hope I helped (:
Have a great day!