What does 2 out of every 3 children mean?

"2 out of every 3 children" means that for every group of 3 children, 2 of them possess a certain characteristic or meet a specific criteria. This can be expressed as a ratio of 2:3 or as a percentage of 66.67%. In practical terms, if you have a group of 6 children, you would expect 4 of them to meet the criteria based on this ratio.