# 7 Maths Hacks That Will Change You!

By Maths Doctor Wednesday, February 18, 2015

## Multiply numbers by drawing

Using a simple example of 12 x 12, which equals 144. By drawing parallel lines anyone will be able to solve from the easiest of multiplication sums to some of the most complex in a short space of time. If we take a look at the diagram below, parallel lines are drawn for each value. For the first number 12, one line is drawn on the left side, and two parallel lines are drawn towards the right hand side. Take the second number 12 and draw one parallel line perpendicular to the previous lines on the top left, and two more parallel lines perpendicular towards the lower right. After taking a look at the diagram, split the diagram into three parts. Each section represents parts of the number. After counting each dissection, the answer will read 144 from left to right. The same would be able to apply to multiplying quadratic equations with the letters and of larger numbers.

## Square any number ending in 5

A cool trick to impress your friends, square any large number ending in 5. A lot of people will say that it is not possible unless you can calculate large sums in your head. Ha, well here’s a cool way to impress them. Let’s take an example, the number 75. Lets square this number, without using pen and paper in 10 seconds. How is this possible? Split the number 75 into two numbers therefore having the number 7 and 5. Multiply the first digit by itself + 1. 7 x 8 = 56. Then just place 25 at the end of the number to get 5625. If you don’t believe this, check your calculator. This can be done with any number ending in 5.

## Pi

Ever wondered what pi stood for except for food of course. Even if we told you, unless you decided to memorize the numbers, that would be a hard feat to accomplish. Pi stands for 3.1415926 to 8 decimal places. If we gave you 30 seconds to remember it, how many of you would be able to come back to me and give a confident answer. Kudos to those who are able. For those who couldn’t, don’t worry, salvation has come with word association. There is a quick and easy statement to remember. “May I have a large container of coffee”. Now how is this related? If you count the number of letters in each word, it will come up to 31415926. Just need to remember the decimal point.

## 9 Times Tables

With Nicky Morgan recently stating that all children by primary school must have the times tables memorised. In this area we will be talking about the 9 times tables. Why am we specifically looking at 9 though? There is a cool neat trick involved in helping remember the products up to 9 x 10. Write the times tables from 9 x 1 to 9 x 10 as shown below. Create two more columns for the answer; within the first column list in ascending order the numbers 0 to 9 and in the second column 9 to 0 in descending order. Who needs to memorise these when we have this neat trick.

## Multiply by 11

Think multiplying a number by 11 is difficult? Not anymore! Let’s take an example of 45 x 11. The answer should be 495. How did we come to that conclusion in such a short space of time? Set aside the numbers 4 and 5 separately. Then add the numbers 4 and 5 to get 9 and place it in-between the two numbers and finally, put the number together as a whole. This applies for all numbers.

## Care for a dance?

Want to learn to dance or a keen dancer? We're sure you’ll be impressed by this one. Ever had problems remembering the graphs of sin(x) or cos(x). With the invention of these fun dance moves, we are sure from now on you will always be able to remember these graphs without having to even think about it. We're sure this one will stay in your head for a while.

## Pretty Butterflies

This one is an interesting one. Do you have problems with remembering the order of adding or subtracting fractions? This is one cool hack that incorporates one of our favourite insects, the butterfly. Set the fraction side by side as you would normally do, and draw two wings along the diagonals made by the numerator and the denominator of the other fraction and draw an antenna on each wing. The wings look like a multiplication sign, so multiply the diagonals and place the products either side of the antenna. The butterfly is now missing its body; if you feel sorry for the butterfly, draw in a body by drawing a loop to connect the bottom parts of its wings, putting the product of the denominators in the body. Add or subtract the numbers in the antennae and voila you have your answer.

As helpful as all these hacks are, the best way to learn maths is to practice the subject regularly. Remember, practice makes perfect.