I hate to admit it, but I never really memorized my multiplications tables as a kid. I was more concerned with playing video games and music. But as an adult, I find myself faced with basic math problems every single day. I’m all about taking the path of least resistance when it comes to learning, so I figure, if I want to get better at math, I’m going to exploit as many tricks and shortcuts as possible.
The beautiful thing about math is that it’s full of patterns. If used correctly, these patterns can make memorization a breeze (or even unnecessary). I recently found a really easy technique for calculating multiples of 9. After just a little practice, I’m able to easily calculate the answer of any basic multiplication problem where a 9 is involved.
First let’s identify the patterns. Here are the first few multiples of 9:
The first pattern I notice is that the tens place is always one less than the multiple.
So if you’re trying to solve 9x6, you know that the answer starts with a 5 in the tens place. Simple! We’re already halfway to the answer. But how can we easily calculate the second number?
This pattern may be a little harder to spot, but if you subtract 10 from the multiple, the difference is the same as the number in the tens place!
Most arithmetic hacks involve taking a complex problem and breaking it down into smaller, simpler problems. Using the technique above, we break a single multiplication problem into two simple subtraction problems. It may take some practice before you’re able to use this technique without hesitation, but stick with it and the answers will start to come naturally.
Have any math hacks of your own? Share them in the comments section below!
Image credit akash_k