M3.1.7 For the adult
Squares, cubes and roots
What does the small raised 2 in 5² mean?
What this chapter teaches
A square number is a square of tiles, and a cube number is a cube of small cubes. The small raised number, the index, says how many copies of the number are multiplied together. A root goes backwards.
Three questions to ask
There is no one right wording. Listen for the idea.
- What does 5² mean, and what is it worth?
- What is the square root of 144, and how do you know?
- Why is the cube root of 8 equal to 2?
After the chapter, the learner can
- Write 2 × 2 × 2 as 2³, and 5 squared as 5²
- Find the square root of a square number up to 144
- Find the cube root of 8, 27 and 64
What they copy into their notebook
5² = 5 × 5 = 25, a square number. 2³ = 2 × 2 × 2 = 8, a cube number. The square root of 25 is 5. The cube root of 8 is 2. The index counts how many of the number you multiply together.