Adding & Subtracting Surds

Lucy introduces the concept of adding and subtracting surds, emphasizing the need for the square root numbers to be the same. She provides an example to illustrate the process and highlights the importance of simplifying surds before performing operations. The video concludes with a brief mention of rationalizing the denominator, which will be covered in a future video.

What is the key rule for adding or subtracting surds?

• The numbers outside the square roots must be the same.

• The numbers inside the square roots must be the same.

• The numbers inside the square roots must be different.

• The numbers outside the square roots must be different.

Why can't you subtract √5 from √3?

• Because they are both irrational numbers.

• Because the numbers outside the square roots are different.

• Because they are both rational numbers.

• Because the numbers inside the square roots are different.

What should you do if the surds have different square root numbers?

• Ignore them.

• Subtract them directly.

• Simplify them first, then see if they can be added or subtracted.

• Add them directly.

What is an important step before performing operations on surds?

• Rationalizing the numerator.

• Multiplying them by a constant.

• Simplifying the surds.

• Converting them to decimals.

What concept related to surds will be covered in another video?

• Adding surds.

• Subtracting surds.

• Rationalizing the denominator.

• Simplifying surds.