3 Reasons to Use Mental Math

I am a huge advocate of mental math. However, there was a time when I questioned what the big deal about mental math was. I was one of those teachers who firmly believed that students should learn how to add and subtract using carrying and borrowing, and that was that! Well, was I ever wrong. When I began teaching mental math, I was astonished at the growth that students experienced. Students who were not “mathematical thinkers” suddenly “got it!” And the students who were already mathematical thinkers became even quicker with their facts! For those of you who are wondering why you should start teaching it, here are three good reasons.

1. Mental Math encourages actual understanding, not just memorization.When you teach students how to add an equation such as 19+23 using carrying, you are teaching a series of steps. For some students, this will work great, and they will catch right on. But for some, it is downright confusing. Where do I put the number? Do I carry the first one or the last one? BUT, when you teach students to break down the numbers and add 10+20 to make 30, 9+3 to make 12, and then 30+12 to make 42, students learn a deep understanding of the numbers. Suddenly that “1” in 19 is not just a 1. It’s a 10. And the “2” in 23 is not just a 2. It’s a 20. Students GET it!

2. Mental Math is logical. It just makes sense. I do think that there is a place for carrying and borrowing, but I am a huge believer that students should learn to do math mentally first. I have had grade 3 students solve an equation like 243+362 in their heads in mere seconds. For real. And that’s without pencil and paper. There is less room for error, and because students are more aware of the numbers, they are more likely to question an answer that doesn’t “look” or “sound” right. {Ever had a student answer a question like 240-150 with some crazy answer like 360 when they’re borrowing and you say to them, “Does that look like it would be the right answer? Let’s think about it…” Well with mental math, students ARE thinking about it right from the beginning, so they won’t make the kinds of mistakes that they do when simply following a series of confusing steps.}

3. Mental Math is fun! It is! I’m serious! When I began teaching this way, I really was re-energized about math. It is easier to understand, easier to do, and just all around exciting! I was actually getting better at math along with my students, which is probably why I’m a bit obsessed with it.