6.4 Exercise 87

Mental math You can use the binomial squares pattern to multiply numbers without a calculator. Say you need to square 65. Think of 65 as $60 + 5$.

1. ⓐ Multiply $\left(60 + 5\right)^{2}$ by using the binomial squares pattern, $\left(a + b\right)^{2} = a^{2} + 2 a b + b^{2}$.
2. ⓑ Square 65 without using a calculator.
3. ⓒ Which way is easier for you? Why?