Originally Posted by blackcat
The example you gave sounds like a ratio or proportion problem and most kids would need instruction on how to set that up and then solve it like an equivalent fraction or cross multiply. I think Khan actually did a decent job explaining that if you go to the sections on ratios.

With the 12% of 20 or whatever problems, remember to keep telling him that OF means "MULTIPLY" in story problems involving decimals or fractions. But you can't multiply a percent you have to convert to a decimal first (my kids struggled with this as well).

You are right -- multiplying by converting to a decimal is what he figured out today. Will go look at ratios on Khan. Thanks!