Math Calculation : Simplified (Part 1)




In Math, calculating numbers can indeed be quite annoying for some students. For example, you are doing a math test and end up spending too much of your precious time calculating 51² or √67. Fear not, for I have a quick and easy solution in squaring and square-rooting numbers.
Just a quick reminder, N in the methods stated below means the number you are trying to square or square root.
Let’s start with squaring 2 digit numbers and the ones that end with 0. These numbers are simple to be squared because all you have to do is to square the first digit then give two zeroes in front of it. Pretty simple, right? Here’s an example: 30². We can calculate this by first giving 3², which is 9, then give two zeroes in front of it, which makes it 900. Easy peasy!

Conclusion, 30 x 30 = 900  à  3 x 3 = 9 and 00 = 900

Another example :          80 X 80 = 6400
And                      :          120 x 120 = 14400

Now, for 2 digit numbers that have 5 in the ones place, just take the digit in the tens place, and then multiply it by that digit + 1. After that you’ll want to give 25 at the back of the result. For example, let’s use 55².
First we take the digit in the tens place, which is 5. Multiply it by that digit + 1. So, 5 x (5+1) = 5 x 6 = 30.
That makes it 30. From there simply give 25 after the number. That makes it 3025, which is exactly 55². This method also works for 3 digit numbers, except you’ll want to take the first two digits instead.

Conclusion, 55 x 55 = 3025 à 5x6 = 30, just put number 25 after it à 3025

Another example :          85 x 85 = 7225 à 8x9 = 72, put number 25 after à 7225
And 3 digit          :           115 x 115 = 13225 à 11x12 = 132 à 13225

See, it’s very easy and will save you a lot of time during non-calculator tests and exams!
That’s it for now! I will show you many other easy Math tricks next time soon. Thank you for visiting my blog!

Nathan ~ Grade 7

Comments

Post a Comment

Popular posts from this blog

Vectors and Scalars

Image
I want to talk about Vectors and Scalars . This is about physics. Now you might be asking, what is a vector? Vectors have a magnitude and direction. In case you don’t know, magnitude is the size of the movement, but it’s not distance. Since it’s a vector quantity, it’s called displacement .  For example, the displacement of a leaf being blown by the wind is 50 centimeters to the east. This is a vector quantity because it has a magnitude (50 cm) and a direction (east). And there’s more...  If someone asks you the version of speed in a vector quantity, it’s called velocity .  For example, the velocity of a ball being thrown is 5m/s to the east. In other words, five meters per second to the east.  You can find the displacement as long as you have the velocity and time. Multiply them and you will get the displacement. If the velocity is 5m/s and the time is 10 seconds, you need to multiply them ( 5 x 10 ) to get the displacement, which is 50 meters.  A...
Read more

Cheryl's Birthday Problem (from SASMO 2015) and Solution

Image
Hello! Nat here, and in this blog, I am going to discuss and give the solution to the famous Cheryl birthday problem. This was popular because it is a difficult logic puzzle and involving the ability of carefully tracking down hints in the conversation and working with only a small amount of data. Here’s the question: Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates. May 15           May 16           May 19 June 17          June 18 July 14           July 16 August 14       August 15       August 17 Cheryl then tells Albert and Bernard separately the month and the day of her birthday respectively. Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard doesn’t know too. Bernard: At first I don’t know whe...
Read more

Black Holes

Image
Black Holes are holes in space that absorbs anything in their way, even stars. They are made by a star exploding as supernova and the star must be about 3 times the mass of the sun. This is called the Oppenheimer-Volkoff limit.  Its core will collapse into a neutron star, but its gravity is so strong that it starts sucking in material from outer space and later turns into a black hole.  Once they absorb enough matter to become powerful and massive, they can start creating galaxies. That is why black holes can be found in the heart of galaxies.  Sometimes, black holes will emit the brightest light waves in the universe – quasars.  Now you might be asking, why don’t we see like “blink, blink” from earth? The answer is that they are very far. The furthest quasar from us is about 14 billion light years away. However, we are lucky to be on a planet that isn’t near a black hole. If we were near a black hole, we would get our atmosphere stripped first then ...
Read more