Skill: Interpret line plots

A line plot shows data on a number line. Each $X$ mark stands for one measurement. To interpret the plot:

1. Read the values on the number line, including fractions such as $\frac14$ and $\frac12$.
2. Count the $X$ marks above each value.
3. Use the measurements and their counts to compare values or find a total or difference.

Suppose this line plot shows the lengths of pieces of ribbon, in inches:

Length	$\frac14$	$\frac12$	$\frac34$	$1$	$(1\frac14)$
Marks	$(XX)$	$(XXX)$	$X$	$(XX)$	$X$

Question: What is the total length of all the ribbon?

Step 1: Match each group of marks to its value.

• Two pieces are $\frac14$ inch: $(2 \times \frac14)$
• Three pieces are $\frac12$ inch: $(3 \times \frac12)$
• One piece is $\frac34$ inch: $(1 \times \frac34)$
• Two pieces are $1$ inch: $(2 \times 1)$
• One piece is $(1\frac14)$ inches: $(1 \times 1\frac14)$

Step 2: Add the amounts.

$$2\left(\frac14\right)+3\left(\frac12\right)+1\left(\frac34\right)+2(1)+1\left(1\frac14\right)$$ $$=\frac12+\frac32+\frac34+2+1\frac14$$

Step 3: Add the fractions.

Convert to fourths:

$$\frac24+\frac64+\frac34+\frac84+\frac54 =\frac{24}{4}=6$$

The total length of the ribbon is $6$ inches.