5 Fast Math Tricks for Multiplication - Mental Math | Summary and Q&A

TL;DR

This video explains various tricks for quickly multiplying numbers, including multiplying by 11, teen numbers, two-digit numbers, and three-digit numbers.

Key Insights

• 🪜 Multiplying by 11 involves adding digits together and carrying over values when necessary.
• ✖️ Multiplying by teen numbers requires adding the units digit and multiplying the units digits individually.
• ✖️ Multiplying two-digit numbers involves multiplying the units digits, adding the cross products, and multiplying the tens digits.

Transcript

good day welcome to the tech math Channel a whole bunch of fast multiplication tricks right now I hope you enjoy them so the first trick we're going to have a look at is multiplying by 11 so say for instance 11 MTI by 134 this is equal to as follows first digit we just put the first digit down here so it's a one the next digit we add these two guys... Read More

Questions & Answers

Q: How do you multiply a number by 11?

To multiply a number by 11, add the digits together and carry over values when necessary. For example, 11 multiplied by 134 is equal to 1,474.

Q: How do you multiply a number by a teen number?

For multiplying by a teen number, add the units digit to the given number and multiply the units digits separately. For example, 13 multiplied by 12 is equal to 156.

Q: What is the trick for multiplying two-digit numbers?

To multiply two-digit numbers, multiply the units digits, add the cross products, and multiply the tens digits. For example, 23 multiplied by 12 is equal to 276.

Q: How do you multiply three-digit numbers?

To multiply three-digit numbers, follow a specific pattern of multiplication and addition. Multiply each digit with each other, starting from the units place and moving towards the left. For example, 132 multiplied by 214 is equal to 28,248.

Summary & Key Takeaways

• Trick 1: Multiply by 11 by adding the digits together and carrying over values when necessary.

• Trick 2: Multiply by teen numbers by adding the units digit to the given number and multiplying the units digits separately.

• Trick 3: Multiply two-digit numbers by multiplying the units digits, adding the cross products, and multiplying the tens digits.

• Trick 4: Multiply three-digit numbers by following a specific pattern of multiplication and addition.