Turning Words into Math
Year 3 Mathematics Math Fun Time Lesson 3 of 10
What Are Algebraic Expressions?
Special maths codes that use letters and numbers Letters like x or n stand for mystery numbers Help us solve puzzles when we don't know all the numbers Make maths problems easier to work with
Quick Warm-Up: Decode the Expressions
Look at these: x + 5 n - 3 2a What do these mean? Write your ideas!
Step-by-Step Translation Process
1. Read the problem carefully 2. Identify what we don't know (the variable) 3. Choose a letter to represent the unknown 4. Identify the operation (add, subtract, multiply, divide) 5. Write the algebraic expression
Worked Example 1: The Apple Problem
Problem: I have some apples. I buy 4 more apples. How many do I have now? Step 1: What do we not know? How many apples I had at the start Step 2: Let a = my apples at the start Step 3: I add 4 more apples Step 4: Answer is a + 4
Worked Example 2: Sam's Pencils
Problem: 'Sam has 7 pencils. He gives some away. How many does Sam have left?' Step 1: What don't we know? How many pencils Sam gave away Step 2: Let p = pencils given away Step 3: Operation is subtracting from 7 Step 4: Expression is 7 - p
Your Turn: Group Challenge
Work with 2 friends Get a story card Find what number you don't know Pick a letter for that number Write it as math Tell everyone how you did it!
Reflection: Why Use Algebra?
Think about it: Why might someone use algebra instead of just numbers? How could algebraic expressions help us in everyday life? What makes algebra powerful for solving problems?