Special Products · Exercise 50

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 $60+5$.

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

This is an open-ended exercise: its source gives no single answer.

OpenStax, Elementary Algebra 2e · §6.4 Special Products · Exercise 50