# Simplifying Surds - WordPress.com Simplifying Surds Look at the example and try to work out how to get to the answer Stuck? Use the hint cards to help (try to only use one at a time!) When you have worked it out, write the rule on your

worksheet: Simplify: 108 When simplifying surds, always look for a factor that is a . Now try the green, amber and red questions! Answer: 6 3

HINT CARD 1 HINT CARD 2 HINT CARD 3 HINT CARD 1 Use the following rule: ab a b a b Simplifying Surds HINT CARD 2 Look

for a factor that is a square number and write it as a sum e.g. 72 9 8 9 8 Simplifying Surds HINT 3 Follow this worked example: 75 25 3 25 3 Look for a factor

that is a square number 5 3 5 3 This is how the final answer should be written Simplifying Surds Squaring Surds Try these sums on your calculator

1. 36 36 What do you find out? 2. 100 100 Write the rule on your sheet: When we square a surd

3. 3 3 Try the green, amber and red sums. 4. 20 20 5. 2136 2136 Why Bother With Surds?

Type each of the sums into the calculator. Look carefully at the answer and think about why we use surds Use the hint card if you need help Write your findings on your

sheet Try the green, amber and red questions These are not surds: 25 225 196 64 81

144 These are surds: 7 24 2 92 12 HINT CARD HINT

Look at the numbers after the decimal point. What words would you use to describe the order that they appear? Why bother with surds? Adding Surds how to collect like terms in algebra? Example:

Remember Adding and subtracting surds works in exactly the same way! Look at the worked example and discuss the question 2 3 4 3 6 3

Your Turn: 8 5 2 3 4 5 3 HINT CARD HINT 1 Think of each surd as x and collect like terms like you would in algebra! E.g. 4 2 23 2

Think of these as 4x 2x = Adding surds Multiplying Surds When multiplying surds, write out the expression in full before attempting to simplify it. Sound familiar? Its exactly the same as algebra!

Can you fill in the working out for this question? Use the hints to help you. Fill in the rule on your sheet: When multiplying surds, always write out Try the green, amber and red questions! Simplify:

3 5 7 2 Answer: 21 10 HINT CARD HINT Write out the sum in the longest way first 2 7 4 6 2 7 4 6 8 7 6

then multiply out the whole numbers then multiply the surds together! 8 42 Multiplying surds