How do we find the Cube Root of a Large Perfect Cube? | Don't Memorise

TL;DR

Learn how to find the cube roots of larger numbers in just five seconds using a simple shortcut method.

Transcript

Now what you're going to see next may astonish you. You will learn how to find cube roots of larger numbers. That is up to six digits. Ah!Come on! Don't worry! And how long do you think you will take to find the cube root of a large number? If you focus hard for the next couple of minutes you will be able to find the cube roots of large numbers in ... Read More

Key Insights

• 🫚 Cube roots of 4, 5, or 6-digit numbers will always be 2 digits long.
• 🧊 Knowing the cubes of numbers from 1 to 10 is essential for this shortcut method.
• 🇦🇪 The unit's digit of a number helps determine the unit's digit of the cube root.
• 🙈 By ignoring the rightmost three digits, we can find the position of the remaining number in the cubes column.
• #️⃣ Choosing the lower number from the corresponding number column gives the tens digit of the cube root.
• 🤩 Practice is key to mastering this cube root calculation method.
• ❓ This method is a shortcut and not suitable for exam purposes.

Questions & Answers

Q: How long does it take to find the cube roots of large numbers using the shortcut method?

With practice, you can solve cube roots of large numbers in just five seconds using this shortcut method.

Q: What are the two important things to know for finding the cube roots of large numbers?

First, you need to know the cubes of numbers from 1 to 10. Second, understand that for 4, 5, or 6-digit numbers, the cube roots will always be 2 digits long.

Q: What is the significance of the unit's digits in the cubes column?

The unit's digits from 0 to 9 in the cubes column are all different from each other, helping us determine the unit's digit of the cube root.

Q: Can this cube root calculation method be used in exams?

This method is a shortcut for quick calculations and cannot be used to solve questions in exams. It can be used to verify answers.

Summary & Key Takeaways

• To find the cube root of larger numbers quickly, you need to know the cubes of numbers from 1 to 10 and that for 4, 5, or 6-digit numbers, the cube roots will always be 2 digits long.

• The first step is to identify the unit's digit of the number and find the corresponding number in the cubes column.

• Ignore the rightmost three digits and focus on the remaining number to determine its position in the cubes column.

• Choose the lower number from the corresponding number column as the tens digit of the answer. Combine the unit's and tens digits to find the cube root.