# WAEC 2020: calculator tricks and shortcuts for mathematics

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Like I always mention, do not skim through this article, read carefully and understand.

## Calculator tricks

It’s important to take note that we are going to be using WAEC’s Kapek® calculator which is quite different from the regular scientific calculator.

Saving Data/values

When working, sometimes there’s is a need for storing our answers in order to carry out another calculation.

#1 type in ur answer.

#2 press the shift button.

#3 press the RCL(STO) button followed by the (-) button.

The calculator will display a message showing that the operation was successful.

You can save more than one data, repeat the steps above again. This time use the °•,,, button instead of (-).

Retrieving saved data

Saving is useless if there is no way to retrieve our data. It’s like teaching a newbie how to fly and not teaching him how to land.

To view your stored data, simply press the RCL(STO) button followed by the (-) key.

Indices (xⁿ)

Sometimes we want to solve indices with a power greater than 3. For example, 10⁴ to do this simply press the 10 ^ 4. Check the image below to see where you can find the ^ key.

Working with fractions

I often see students convert fractions to decimals before they can solve it with the calculator, some prefer using a divide which can make your work messy.

One way to do this is to use the ab/c key.

For example if you want to type 7⅓ , follow this pattern 7 > ab/c >1> ab/c > 3. The calculator is not a natural display, it will appear like this 7>1>3. You can also convert decimals to fractions using the same key.

Typing Alphabet

The alpha key is not available on the Kapek® calculator. However, it is still possible to type the alphabet. Press the RCL(STO) button followed by any of the buttons in the yellow circle below.

Check the image below to see how

## Mathematics Shortcuts/tricks

You don’t have to press your calculator every time you want to check if a particular number is divisible by another. It slows down your work.

Division Test

#1 Divisible by 2 – the number will end with an even number or zero.

#2 Divisible by 3 – add all the digits of the number, if the sum is divisible by 3 then it is a factor.

#3 Divisible by 4 – the last two digits of the number will be divisible by 4.

#4 Divisible by 5 – the number will end with zero or 5

#5 Divisible by 6 – A number is divisible by 6 if it is even and if the sum of its digits is divisible by 3.

#6 Divisible by 8 – the last three digits of the number will be divisible by 8.

#7 Divisible by 9 – the sum of the digits of the number will be divisible by 9

#8 Divisible by 10 – the number will end with zero.

Conversion of units

With this simple trick, you don’t have to cram your measurement table. For example, if you want to convert kilometer to a meter. This is not common in mathematics but it is very useful when it comes to physics.

The method is called King Herod’s Daughter.

#1 write down the acronym KHDMDCM at the back of your note.

#2 One way to cram the acronym is to say it like this “King Herod Daughter Must Die Cooking Meat”.

#3 K means Kilo, H means Hecto, D means Deca, M means Meter or gram when measuring weight and liter went measuring volume, the second D means Deci, C means centi and the second M means milli.

Let’s say you want to convert 1 kilometer to meter, write 1 under the K, and write zero to the rest till it reaches the M. This shows that 1000m make 1kg.

Check the image below for clarity.

The more you practice, the faster you become.

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