Chapter 10
Exponents and square roots
Writing 2 × 2 × 2 × 2 × 2 out in full is slow and easy to miscount. An exponent is the short way of saying it: 2⁵.
A square root asks the question backwards. Instead of what 6 × 6 comes to, it asks which number multiplied by itself makes 36.
Exponents and square roots
An exponent tells you how many times to multiply a number by itself. A square root asks which number times itself makes the number you have.
- 5² means 5 × 5, which is 25.
- 2³ means 2 × 2 × 2, which is 8.
- A square root undoes a square.
Finding a square root
√36 = 6
because 6 × 6 = 36.
Key words
Much of pre-algebra is vocabulary. A question names what it wants in these terms, and the term decides which arithmetic answers it.
- Exponent
- A small raised number that says how many times to multiply the base by itself.
- Square root
- The number that gives you your number when it is multiplied by itself.
Where this leads
- The scientific calculator
- It has keys for powers and roots, so a square root of a number that is not a whole answer can be worked out.