Fast Math Tricks - How to multiply 2 digit numbers up to 100 - the fast way! | Summary and Q&A

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November 26, 2011
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tecmath
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Fast Math Tricks - How to multiply 2 digit numbers up to 100 - the fast way!

TL;DR

Learn a fast and efficient method for multiplying two two-digit numbers together, improving mental math skills.

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Key Insights

  • ✖️ The fast method of multiplying two two-digit numbers involves multiplying the first digits, last digits, and pairs of digits in between.
  • 👻 The method allows for a quicker calculation of multiplication problems and improves mental math skills.
  • 👾 Carrying over extra digits may be necessary when there is limited space for the digits in the answer.

Transcript

G'day and welcome to the TecMath channel.
In this video today we are looking at the fast way of multiplying two two digit numbers together....so let's go! First of all we'll see if you can multiply some numbers together I'll give you a question which is twenty-one times thirty one.
I'll give you six seconds to work that out. Go! So time's up. ... Read More

Questions & Answers

Q: How do you multiply two two-digit numbers together quickly?

You can use a simplified method where you multiply the first digits and place the result in the first digit of the answer. Multiply the last digits and place the result in the last digit of the answer. Multiply each pair of digits and add them together to get the middle digit(s).

Q: What if there is only one space for the digits in the answer?

If there is only space for one digit, the extra digit has to be carried over to the next place value. For example, in the multiplication of 43 and 21, the answer of 10 is obtained by adding 1 x 4 and 3 x 2, and the 1 is carried over to the next step.

Q: How can practicing this method improve mental math skills?

By practicing this method, you can become faster at mental math and improve your ability to perform multiplication calculations without relying on a calculator. This will impress teachers and make you more efficient in solving math problems.

Q: Are mistakes common when using this technique?

It is possible to make mistakes when using this method, especially if you rush through the steps. However, with practice and attentiveness, the chance of making mistakes decreases.

Summary & Key Takeaways

  • The video teaches a simplified method for multiplying two two-digit numbers together.

  • The first digit of the answer is obtained by multiplying the first digits of the two numbers.

  • The last digit of the answer is obtained by multiplying the last digits of the two numbers.

  • To get the middle digit(s), multiply each pair of digits and add them together.

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