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Read max, min, and gridline scale from a line graph

The line graph shows the number of ice cream cones sold each day at Mia's ice cream shop. Find the difference between the number sold on the busiest day and the number sold on the slowest day.

The graph is titled "Ice Cream Cones Sold." The horizontal axis shows the day of the week (Mon, Tue, Wed, Thu, Fri), and the vertical axis shows the number of cones sold. The vertical axis is labeled 500, 600, and 700; since 5 grid squares represent 100, each grid square represents $100 \div 5 = 20$ cones. The daily sales are: Monday $520$ , Tuesday $660$ , Wednesday $580$ , Thursday $740$ , and Friday $680$ cones.

Measurement & data

Your answer

cones

How to solve

Strategy Draw a Diagram — On a line graph the highest dot is the maximum and the lowest dot is the minimum, so I read those two points off the graph and then subtract. The work splits into find-max, find-min, subtract.

1STEP 1

Find the busiest day

The highest point is Thursday, two squares above 700: 700 + 2 × 20 = 740 cones.

700 + 2× 20 = 740

2STEP 2

Find the slowest day

The lowest point is Monday, one square above 500: 500 + 20 = 520 cones.

500 + 20 = 520

3STEP 3

Subtract

The difference between the busiest and slowest day is 740 - 520 = 220 cones.

740 - 520 = 220

Answer

220 cones

740 - 520 = 220

740 is the highest reading and 520 the lowest, and 740 - 520 = 220, which is 11 squares of 20 cones (11 × 20 = 220) - consistent with the grid. The difference is less than either total, as a difference should be.

Takeaway

Highest dot minus lowest dot - just remember each square here is worth 20!

Find the busiest day
Find the slowest day
Subtract

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