Square roots

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Finding a square root of a number is the opposite of

squaring a number.

Squaring a number means multiplying the number by itself. For example,

(read as "four squared") means

Finding the square root of a number is the opposite. A square root of a number is a number you can square to get the original number. For example, a square root of 16 is 4, because

You can show a square root with the symbol √.

Fun Fact

When you square a whole number, you get a number called a perfect square. For example, 16, 25, and 36 are all perfect squares. Their square roots are whole numbers.

Try some practice problems!

Square roots of perfect squares

Squaring negative numbers

You can also square negative numbers. Multiply the negative number by itself.

For example, you can square

–

Remember that a negative times a negative is a positive.

(

–

)

(

–

)

(

–

)

So,

(

–

)

Note that since

(

–

)

then

–

is a square root of 25.

Videos(3)

Square roots of perfect squares

Estimate positive square roots

Positive and negative square roots

Lessons

Square numbers

Cube roots

Try some practice problems!

Squaring negative numbers

Try some practice problems!

Try some practice problems!

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