Discovering Square Roots and Radicals
Year 7 Mathematics Learning to use the √ symbol Finding square roots of numbers
What do you notice about these numbers?
4 × 4 = 16 5 × 5 = 25 6 × 6 = 36 7 × 7 = 49
What are Square Numbers?
A square number is made when we multiply a number by itself Examples: 1×1=1, 2×2=4, 3×3=9 We can arrange them in square patterns The first few square numbers are: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100
Introducing the Square Root Symbol
The symbol √ is called the 'radical sign' It means 'square root of' We read √16 as 'the square root of sixteen' The square root asks: 'What number times itself gives this answer?'
Let's Practice Reading Square Roots
Read these aloud: √9 √64 √100 √49
Understanding Square Roots
{"left":"If 4 × 4 = 16, then √16 = 4\nIf 5 × 5 = 25, then √25 = 5\nIf 6 × 6 = 36, then √36 = 6","right":"If 7 × 7 = 49, then √49 = 7\nIf 8 × 8 = 64, then √64 = 8\nIf 9 × 9 = 81, then √81 = 9"}
How to Find Square Roots
Ask yourself: 'What number times itself gives me this answer?' For √36, think: 'What number × itself = 36?' Since 6 × 6 = 36, we know √36 = 6 Start with square numbers you know: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100
Square Root Challenge
Find these square roots: √1 = ? √4 = ? √9 = ? √16 = ? √25 = ?
Remember This!
The square root of a number asks: 'What number times itself gives this result?'
Today We Learned
The √ symbol means 'square root' Square roots are the opposite of squaring numbers √16 = 4 because 4 × 4 = 16 We can find square roots by asking 'what number times itself gives this answer?' Practice with perfect squares: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100