Do you want to help your kids improve their reading comprehension so that they can get better grades in school and achieve success on all standardized tests?
Reading is the key to everything. And vocabulary and grammar are the keys to reading--even in mathematics.
Math is not simply calculating numbers. It's reading in order to gain the information that you need to reason towards a solution. This is why calculators don't help. Math requires reasoning and analysis. These are the same skills required in reading, vocabulary, and grammar. If you cannot read, you cannot reason. And if you cannot reason you cannot succeed in math or any other subject.
The way they teach reading is wrong because it doesn't require or enhance reasoning skills.
Words must be learned from context and from etymology since both of these approaches if done correctly sharpen and create a host of transferable metacognitive skills.