- 01. Converting Between °F to °C
- 02. Cool Maths Trick - Know the Day on Any Given Date
- 03. Multiply Big Numbers in your Head
- 04. Multiplying by 11
- 05. Remembering Pi
- 06. Squaring Any Number
- 07. Adding and Subtracting Fractions
- 08. Recognizing Products
- 09. Converting Salaries into an Hourly Rate
- 10. Squaring Multiples of 5
Do you feel like you're always lost in a maths class? Has it been like this for years? Do you have trouble with specific branches in mathematics or is it the entire subject you find challenging?
Well, the good news is that you are not alone! As a matter of fact, many students pick online math tutoring to improve their skills.
To understand math teachers better continue reading and find some tips that will change your life.
Aren't entirely sure? By the end of this article, you'll know how to multiply large numbers without a calculator.
There are many skills, tricks, and techniques that no one is teaching at school but are really useful in our everyday lives. But, don't worry, we're not talking about tricks to solve polynomial, differential, exponential or linear equations.
One thing’s for certain, you’re going to get better at maths!
These tricks aren't for complex operations. Just a few algebraic tricks that you won't find in your maths revision SAT guide! These are just to show you how to solve math problems in life.
Converting Between °F to °C
The United States is probably the only country in the world that uses °F to measure temperature. The rest of the world uses °C.
If you travel or live abroad you're going to have to learn how to convert these two. If you can do simple addition and subtraction and even simpler multiplication and division, then you'll have no problem.
You can convert °C to °F, just multiply it by 2 and add 30. This simple math trick works every time!
In fact, the real conversion multiplies the number by 1.8 (a ratio of 9/5) before adding 32. But this method is simplified by rounding to a whole number so that you can work it out in your head.
Some important facts you should know:
- 0°C = 32°F, water freezes.
- 100°F = 38°C, body temperature.
- 100°C = 212°F, water boils.
You inverse it to convert the other way round. Subtract 30 then divide by 2. Both these methods are great for estimating and work to some extent with negative numbers, too.
Cool Maths Trick - Know the Day on Any Given Date
This might sound crazy to you but once you get the basics you should be able to calculate what day it was on any given calendar date.
You don’t need to be enrolled in maths classes or get a Master’s in Maths to learn some basic maths formulas and work out some calculations in your mind.
Get an elementary math tutor here now.
Step 1: Remember the value for the months
- January = 1
- February = 4
- March = 4
- April = 0
- May = 2
- June = 5
- July = 0
- August = 3
- September = 6
- October =1
- November = 4
- December = 6
Step 2: the years
- 1700s = 4
- 1800s = 2
- 1900s = 0
- 2000s = 6
Step 3: Once you've remembered these tables the method is as follows. So for October 10, 2012:
- Take the last two digits of the year, "12".
- Divide them by 4. 12/4 = 3
- Add the day of the month, "10". 3 + 10 = 13
- Add the month's value from the table, "1". 13 + 1 = 14
- Add the century code, "6". 14 + 6 = 20
- Add the last two digits of the year, "12". 20 + 12 = 32
- Divide by 7. 32/7 = 28, with a remainder of 4. This makes it the fourth day of the week (with Sunday being the first).
Just keep practicing and you'll get it!
Multiply Big Numbers in your Head
Instead of doing the multiplication in the calculator or a piece of paper, here is how you can multiply large numbers in your head! Having this skill will help you in any math class.
For example 97 x 96
100 - 97 = 3 and 100 - 96 = 4.
Then these two results together. 4 + 3 = 7.
Take 7 from 100 to get the first two digits of the answer. 100 - 7 = 93.
Then, take the two numbers from step one and multiply them together to get the last two digits of the answer. 3 x 4 = 12.
96 x 97 is: 9312.
Multiplying by 11
Did you ever learn the classic rule for multiplying by 11 in which you sum the first and last number and put it in the middle?
13 x 11 = 143 because 1 (the first number) + 3 (the digit at the end) = 4, which we put in the middle of the number 13.
But this only works with 2-digit numbers.
Below we show you how to do this operation, particularly 3-digit numbers, by 11.
Let’s work out 51236 x 11.
Start by adding the digit “0” before the number, so we get 051236.
Then, you need to add the last two numbers and put the result between said numbers.
Let’s have a go. So:
For 051236, do the following:
Keep the 6 because it’s the last digit. Therefore, 6 + 0 = 6.
3 + 6 = 9
3 + 2 = 5
2 + 1 = 3
1 + 5 = 6
And the last is 0 + 5 = 5
We therefore get: 563596
For some students, either in high school or college, this number is a nightmare. Have you ever tried to figure out a way to remember all the digits after the decimal point that make up this irrational number?
It just so happens that poetry can help you learn maths! The following 4-line poem can help you remember the digits of Pi by counting the letters in each word.
"Now, I wish I could recollect pi.
"Eureka," cried the great inventor.
Christmas Pudding; Christmas Pie
Is the problem's very center."
“Now” = 3, “I” = 1, “wish” = 4, etc.
There are also expressions to remember the first 8 digits.
Just say: May I have a large container of coffee?
Just like before, count the letters in each word. Does Maths bring financial literacy?
Now back to rational numbers...
Squaring Any Number
You might think squaring is impossible to do without a calculator but, there is a quick trick to square any number in your head. Just keep in mind that this trick doesn't work for square roots.
To square a number “X”, you need to find “D”, the difference between X and the closest multiple of X.
Then you need to carry out the following operation: (X - D) and (X + D).
For example, if you want to work out the square of 84, the nearest multiple of 10 is 80, making 4 your “D”.
X + D = 88 and X - D = 80.
Therefore 88 x 80 = 6400 + 640 = 7040.
Add 4 squared, 16, and you’ll get 7056.
Adding and Subtracting Fractions
Understanding addition and subtraction on fractions can be confusing but it is not impossible! By understanding and using the “Butterfly” method, you’ll be able to work out all your fractions in maths class.
For adding fractions you need to find the common denominator and to do this students have to multiply the two denominators to get the same denominator.
With the common denominators, you add the numerators and you’ll get a new fraction with the new denominator.
Find senior math classes here.
3 /4 + 2/5 = (3x 5) / (4×5) + (2 x 4) / (5 x 4) = 15/20 + 8/20 = 23 /20.
This also works for subtraction.
It's called the butterfly method because the wings of the butterfly represent cross multiplying. This will give you maths help and you'll get better at maths and problem-solving!
For any calculation, you need to recognize the main products, this will really simplify mental arithmetic.
- Multiples of 2: These numbers are always even numbers.
- Multiples of 3: These numbers always add up to a multiple of 3.
- Multiples of 5: These always end in 0 or 5.
- Multiples of 9: The digits of these numbers always add up to a multiple of 9.
- Multiples of 10: Every number that ends in 0.
Converting Salaries into an Hourly Rate
Knowing the hourly rate of a salary is important, and here is how to calculate it:
Say you’re paid X amount per year but you don't want to know years, you want to know how much you make each hour.
You can get the answer by taking the annual salary, taking off the last three zeros, and then dividing this number by two.
So, if you earn 30,000 a year, that means 30/2 = 15. So around 15 an hour.
If you need help, ask one of our many online math tutors!
Squaring Multiples of 5
To save time, calculating the squares of multiples of 5 can be really useful.
Take 35, for example.
Multiply the tens digit by itself plus one.
Then add the number 25 as a suffix.
This means 35² = 3 x (3+1) = 12 then add “25” as the suffix, so 1225.
You can use this for any multiple of 5.
105² = 10 x (10+1) = 110 and the suffix “25”, making 11025.
If you graduated from school years ago, you’ve probably forgotten most of the formulas that you learned in maths class.
To boost your knowledge without going back to square one, use these maths tips! You'll be able to identify the different methods, impress your friends, and improve your numeracy.
Know that this is important because we use maths all the time. So how many maths classes do you need?
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