Divisibility Tricks with Sweet Rewards

We are only a couple of days from Halloween, so let's learn a couple of math tricks involving divisibility. Has your student been struggling with finding factors of numbers, well let's help them out with the following tips.

In order for a number to be divisible by 2 the number has to be even. Not sure what makes a number even, it has to have a 0, 2, 4, 6, or 8 in the one’s place.

For example, 62 is divisible by 2 because it is even, however, 99 is not as it is an odd number.

In order for a number to be divisible by 3, the sum of the digits is divisible by 3. This one might sound confusing, but let’s elaborate.

For example, let’s look at 8,703. First we add the digits together, so we have 8 + 7 + 0 + 3 = 18. Now, we ask ourselves, is 18 divisible by 3. Which is true because 3 x 6 = 18. So, 8,703 is divisible by 3.

In order for a number to be divisible by 4, find half of the number, then find half of it again and make sure you have a whole number.

For example, let’s look at 384. First, let’s take half, which is 192. Then take half again which is equal to 96. Therefore, 384 is divisible by 4.

Let’s look at a counterexample. If we have the number 70, notice we can take half of it which would be 35. However, we cannot evenly take half of 35, so 70 is not divisible by 4.

There are many more divisibility tricks that your student can learn here at Mathnasium with our unique teaching method customized to each individual student. Schedule a consultation appointment today to see how Mathnasium can be suited for your student’s needs.