standard_description: Understand the meaning of the equal sign, and determine if equations involving addition and subtraction are true or false. For example, which of the following equations are true and which are false? 6 = 6, 7 = 8 – 1, 5 + 2 = 2 + 5, 4 + 1 = 5 + 2.
problem_activity: Problem 1
At the store, you see oranges on sale at 1 pound for $3. At a different store, your brother sees oranges on sale at 3 pounds for $8.
Do the oranges cost the same at both stores? Which store offers the better deal? Justify your answer.
Problem 2
Callie biked 12 miles in 3 hours. Carter biked 10 miles in 2 hours.
Represent each person's trip with a double number line. Explain how you can see that they are not going the same speed.
Problem 3
Density is the relationship between the mass of an object and its volume, or amount of space it takes up. A scientist finds a rock and determines its mass to be 18 grams and its volume to be 4 cm
$$^{3}$$
. Another rock is found with a mass of 63 grams and a volume of 14 cm
$$^{3}$$
.
Draw two double number lines to compare the two rocks. Do the rocks have equivalent ratios of mass and volume? Do they have the same density?


aligns: no