This approach can be used for even larger numbers.
SIMPLE MATH TRICKS FORMULA PLUS
We can reduce it by first calculating 30 × 7 (which is like 3 × 7 plus a 0) and then add 6 × 7 on the result. In order to solve simple multiplication, it helps a lot being comfortable with the multiplication table for numbers below 10.Īs you may have already guessed, we’re going to use the left to right approach to solve simple multiplication very easily. You can use this technique to solve subtraction readily. This way you don’t have to worry about borrowings. You can, however, subtract 20 to 64 and add 3 to the result.
In this case, you first start by subtracting 10 to 64, resulting in 54, and now you only have to subtract 7 to 54. This time, however, it may feel uncomfortable to keep track of borrowings (a borrowing occurs when you subtract a number to a bigger one, like 16 – 9). You can use the left to right approach for subtracting to numbers together. Simplify it even further by adding 30 to 1049, and then you finally add 7 to the result. Now the problem is simplified to 1049 + 37. You first start by adding 600 to 459, which results in 1059. This example is a bit more complicated than the previous one, yet it’s very easy to solve using the left to right approach. If you’re working with three digit numbers, the process is the same. Although this example is very simple, you’ll see the advantages of this method as you start to use it. By using the left to right approach, you first sum up 30 to 45, and then you add 4 to the result. Usually, you would first sum up 4 to 45, and then add 30 to the result. This works well on paper, but it’s not so easy for mental calculations. With this method, you first sum the decimal part of the number, then you move to the hundreds and so on. To find out the 5% of a number, divide it by 10 and the divide it by two.Īt school, we were mostly taught to sum two or more numbers using the right to left approach.To find out the 20% of a number, divide it by 10 and multiply the result by two.To find out the 15% of a number, divide it by 10 and the add half of it.
To multiply by 9, simply multiply by 10 and then subtract the number itself. If you want to find the square of 25 for example, you take the first digit (2), multiply it by the next higher number (3), and then add 25 to the result. To calculate the square of a number below 100 is extremely simple. Square any two digit number that ends with 5 If the sum of the two numbers is bigger than 9, you add 1 to the first number, then just use the second digit of the addition of the two numbers (you add ‘5’ because the sum of 8 + 7 is 15), and then add the second number.Ģ. Just write the first digit, then add the first and second digits together, followed by the second digit again. There is, however, a simple trick that’ll do the job for any two digits number. One way to find it would be to multiply 36 by 10 and then add 36 on the result. Let’s say that you want to multiply 36 and 11.
SIMPLE MATH TRICKS FORMULA HOW TO
How to multiply any two digits number by 11
If you’d like to learn some mental arithmetic shortcuts now, read on …. The problem is, not all of us picked this up in school.
Being able to quickly perform addition, subtraction, multiplication and division is sure to impress your friends.
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