options: Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.

Apply the properties of operations to generate equivalent expressions. For example, apply the distributive property to the expression 3 (2 + x) to produce the equivalent expression 6 + 3x; apply the distributive property to the expression 24x + 18y to produce the equivalent expression 6 (4x + 3y); apply properties of operations to y + y + y to produce the equivalent expression 3y.

Write, read, and evaluate expressions in which letters stand for numbers.

Write and evaluate numerical expressions involving whole-number exponents.
problem_activity: A cube has
$$6$$
equal sides, each with an area of
$${s^2}$$
square units. The surface area of a cube is the total area of all six sides, and is represented by the formula
$$S=6{s^2}$$
.
Find the surface area of a cube with the side lengths below.
a.
$${s=3}$$
inches
b.
$${s=1.2}$$
cm
c.
$${s={2\over3}}$$
ft


correct_option_index: 2