Reading Graphs & Estimation — Drills
Reading Graphs & Estimation has 5 drill skills. Each one generates fresh questions every time, with a hint and full worked steps, so you can keep practising a single skill until it settles.
What these drills cover
These questions use 8 ideas from the course. Follow any of them for a definition, where it is taught, and what it leads to.
- Rate — A ratio of two different units, like miles per hour or dollars per pound.
- Percent — Parts per hundred. 37% = 37100 = 0.37.
- Area — Space inside, measured in square units.
- Bar graph — Compares separate categories.
- Line graph — Shows change over time.
- Circle graph — Shows parts of one whole, as percentages summing to 100%.
- Dimensions — Rows × columns. A 2 × 3 matrix has two rows and three columns.
- Height — The perpendicular distance from the base to the opposite corner.
Choosing the method
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
Which graph best shows how a monthly budget splits into categories?
- Circle graph
- Line graph
- Bar graph
Worked answer
Circle graph
Circle graph is the right choice here.
Problem 2
Which graph best shows a plant's height measured each week for two months?
- Circle graph
- Line graph
- Bar graph
Worked answer
Line graph
Line graph is the right choice here.
Readcircle
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
A circle graph shows that 20% of 1,200 people chose one option. How many people is that?
Worked answer
240
0.2 × 1200 = 240
Problem 2
A circle graph shows that 18% of 200 people chose one option. How many people is that?
Worked answer
36
0.18 × 200 = 36
Estimate
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
Estimate 576 × 47 by rounding.
Worked answer
30000
600 × 50 = 30000
The exact value is 27072.
Problem 2
Estimate 784 × 28 by rounding.
Worked answer
24000
800 × 30 = 24000
The exact value is 21952.
Misleading
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
A bar chart has a vertical axis starting at 80 instead of 0. One bar reaches 85 and another 89, so the second looks far taller. What is the actual difference?
Worked answer
4
89 - 85 = 4
Only the part above 80 is drawn — 5 against 9 — which is why one looks so much bigger.
Problem 2
A bar chart has a vertical axis starting at 50 instead of 0. One bar reaches 54 and another 62, so the second looks far taller. What is the actual difference?
Worked answer
8
62 - 54 = 8
Only the part above 50 is drawn — 4 against 12 — which is why one looks so much bigger.
Readline
Unlimited questions of this kind are generated in the app. Two examples:
Problem 1
A line graph shows temperature rising from 13° to 49° over 4 hours. What is the rate of increase per hour?
Worked answer
9
49 - 13 = 36 degrees
36 ÷ 4 = 9 degrees per hour
Problem 2
A line graph shows temperature rising from 17° to 37° over 4 hours. What is the rate of increase per hour?
Worked answer
5
37 - 17 = 20 degrees
20 ÷ 4 = 5 degrees per hour