Graphs & Data Interpretation
A graph is data in disguise — read the scale, pull the values, then do the math.
1 Explore — try these first
Try before you watch. Pick a level below and give the problem an honest try on paper first — wrong turns and all. Then open the video to see the trick. Every level rides one habit: Read the axes and the scale first; the picture stores the data, you do the arithmetic.
★ · Read the Scale
A small relief bar graph shows bottles handed out by station. The vertical axis is gridded so that one square equals 5 bottles. Station A reaches 4 squares tall and Station B reaches 3 squares tall. How many bottles did Station A hand out?
L0 · Graph + Clue
A bar graph shows snacks served Monday through Thursday: 20, 15, 25, 10. A clue at the bottom reads, 'On Friday, 5 more snacks were served than on Thursday.' How many snacks were served Monday through Friday in total?
L1 · Decode the Scale, Then Combine
A 'Supplies collected' bar graph is gridded so that one square equals 4 items. Blankets stand at 5 squares, Water at 7 squares, Food at 6 squares, Kits at 3 squares. How many more items were Water and Food combined than Blankets and Kits combined?
L2 · Compare the Pair
A double bar graph for 'Needed vs Delivered' shows Monday through Thursday. Needed: 25, 30, 35, 40. Delivered: 20, 30, 35, 35. What was the total shortage for the week?
L3 · Read the Jump
A line graph shows the water level in a reservoir at 1, 2, 3, 4 and 5 pm: 10, 18, 21, 33, 36 cm. What was the biggest one-hour rise during the afternoon?
L4 · Subtract for the Interval
A cumulative line graph shows total meals delivered by end of day for Days 1–4: 40, ?, 160, 220 — a straight line. Day 2 is shown only as '?' between gridlines and must be derived. Day 3's meals were split between two teams in a 2:1 ratio. How many meals did the larger team deliver?
L5 · Link Two Graphs
Graph A is a cumulative line of meals delivered with end-of-Week 1 at 120 and end-of-Week 2 at 300. Graph B is a bar chart of teams working in Week 2, showing 6 teams. How many meals did each team deliver in Week 2?
L6 · Data Detective
A cumulative line graph shows total meals delivered by end of day for Days 1–4: 60, 180, 260, 300. Phase 1 (Days 1–2) ran with 5 teams; Phase 2 (Days 3–4) ran with 4 teams. By how much did each team's per-day rate drop from Phase 1 to Phase 2?
2 Learn — watch the solutions
Gave each one a real try? Now watch the trick. (Stuck is fine — that's the point.)
★ · Read the Scale
Peek the trick — Height times scale
Before reading any bar, find what one square is worth. A bar's value equals its height in squares multiplied by that scale.
L0 · The Graph and the Clue
Peek the trick — Read, then add the off-graph clue
First read the exact values straight off the graph. Then apply the extra sentence-clue — the value that lives in words, not on the bars — before you combine.
L1 · Mind the Scale
Peek the trick — Scale up every bar first
When one square is worth several units, multiply every bar by the scale before you add or compare. Forgetting the scale is the classic trap that turns 20 squares into 20 items.
L2 · Compare the Pair
Peek the trick — Gap in each pair, then total
A double bar graph is about pairs. Compare the two bars in each pair, take the gap (a day that met its need adds 0), and total all the gaps.
L3 · Read the Jump
Peek the trick — Compare changes, not points
On a line graph the answer is usually the CHANGE between neighbouring points, not a single point. List the jumps and pick the steepest.
L4 · Subtract for the Interval
Peek the trick — Subtract the cumulative neighbours
A cumulative (running-total) graph hides each day's amount. If a total isn't marked, recover it from the straight line as the midpoint of its neighbours, then subtract consecutive totals to get one period's amount.
L5 · Two Graphs, One Answer
Peek the trick — One graph for total, one for count
When two displays describe the same situation, use one for the TOTAL and the other for the COUNT, then divide for a per-unit RATE.
L6 · Data Detective
Peek the trick — Chain subtract then divide
No single read closes it. Subtract along the cumulative graph to recover each phase's total, divide by (days × teams) for each phase's per-unit rate, then compare the two rates.
3 Master — practice on your own
Print the practice sheet and solve without the videos. Check your answers at the back — if one is wrong, the answer key names the trick so you know exactly which video to rewatch.
Download fresh practice problems PDF
