Calculating Square Roots Mentally

The video by Preshtalwalker teaches how to calculate the square root of perfect squares mentally, a skill once essential for students in 1876 without calculators. The method involves memorizing squares of numbers 0-9 and using the last digit to determine possible square roots. Several examples illustrate the method, including adapting it for cube roots. The video concludes with a historical reflection on arithmetic's evolution, highlighting the significance of Indian numerals in simplifying calculations.

What is the main focus of the video by Preshtalwalker?

• Calculating cube roots using a calculator

• Learning to calculate square roots of perfect squares mentally

• Understanding the history of Roman numerals

• Solving complex algebraic equations

Why was the skill of calculating square roots mentally important in 1876?

• It was used in art and design

• Calculators were not available

• It was a requirement for all jobs

• It was a popular hobby

What is the first step in the method taught in the video for calculating square roots?

• Drawing a number line

• Using a calculator

• Memorizing the cubes of numbers

• Memorizing the squares of numbers from 0 to 9

In the example of calculating the square root of 1600, what is the last digit of the square root?

• 0

• 4

• 8

• 6

For the square root of 4225, what is the last digit of the square root?

• 7

• 5

• 9

• 2

When calculating the square root of 841, which two numbers are considered for the last digit?

• 1 and 3

• 4 and 6

• 2 and 8

• 1 and 9

What is the square root of 3969?

• 63

• 62

• 64

• 61

How is the method adapted to calculate the square root of 11.56?

• By using a calculator

• By considering it as 1156 and then dividing by 10

• By estimating the value

• By using a logarithm table

What is the square root of 16384?

• 124

• 126

• 128

• 130

What is the first step in adapting the method for cube roots?

• Drawing a cube

• Using a calculator

• Memorizing the cubes of numbers from 0 to 9

• Memorizing the squares of numbers