UK Secondary (7-11)
Evaluate expressions involving numerical roots

## Interactive practice questions

Which of the following is true for a principal square root?

None of these statements are true.

A

There are two principal square roots of any positive number.

B

The values of principal square roots are always positive.

C

It is only possible to find the principal square root of a positive number.

D

None of these statements are true.

A

There are two principal square roots of any positive number.

B

The values of principal square roots are always positive.

C

It is only possible to find the principal square root of a positive number.

D
Easy
Less than a minute

Write the principal square root of $16$16.

Do not evaluate it.

Write the negative square root of $49$49.

Do not evaluate it.

Peter said that $\sqrt{441}$441 is equal to $21$21 because $441$441 is actually $21^2$212, which is $21\times21$21×21, so the square root of this is just $21$21. True or false?