what is missing in the problem?

the number of red marbles from the total number of 220 marbles.

solution:

convert 10% into digit form

10%= 0.10

then multiply it by 100

0.10×100=10

then divide 10 from 220

220÷10=22

final answer: therefore, the number of red marbles from the total number of 220 marbles are 22 red marbles.