How do people multiply big numbers in their head?

Multiply one of the numbers in its entirety with the first part of the other broken down number. For example 320×20. If this is too much for you, then break down the numbers even further: 32 and 0, and 2 and 0. Multiply 32×2 which is 64.

How do you calculate maths fast in your head?

10 tricks for doing fast math

1. Adding large numbers. Adding large numbers just in your head can be difficult.
2. Subtracting from 1,000.
3. Multiplying 5 times any number.
4. Division tricks.
5. Multiplying by 9.
6. 10 and 11 times tricks.
7. Percentage.
8. Quickly square a two-digit number that ends in 5.

What strategies can you use to add large numbers?

Addition Tips and Tricks

• Count From A Number Upwards. Example: 6 + 3.
• Jump Strategy. We can also count by 2s or 10s, or make any “jumps” we want to help us solve a calculation.
• Adding Up To Ten.
• Do The Tens Last.
• Aim for Ten.
• Compensation Method.
• Double when the numbers are the same.
• Double if the numbers are close, then fix.

How do geniuses multiply large numbers?

First of all, most geniuses multiply large numbers the same way everyone else does, with a calculator. But specifically geniuses who focus on calculations use a number of different techniques.

How do you multiply numbers with different parts?

Multiply the same first number with the second part of the second number. For example, multiply 320×3. If, again, it is easier for you to break this down even more, than multiply 32×3 and save that zero to add on to the end result. 32×3 is 96, place the zero on the end and your product is 960.

What is a mental multiplication trick?

This mental multiplication trick uses the idea of a third number – a base number – to help us multiply two numbers in your head. This series of videos first looks at multiplying numbers near 10 using base 10.

What is the quickest way to multiply numbers with multiplication?

The quickest way is to start with the 4 from the 40 that we carried, then add on the 4 × 6 and 7 × 3: These addition-multiplication pairs are quick to do with practice. Again we can write down the “9” in the tens place of the final answer, and keep the 4 for the following step.