Comparison Methods

Techniques for comparing values: finding differences, totals, and relative sizes.

Learn

Techniques for comparing values: finding differences, totals, and relative sizes.

Comparing data involves several methods: finding the difference (subtraction), computing totals (addition), identifying maximum and minimum values, and calculating ratios or percentages. The comparison method depends on the question—'how much more' asks for difference, 'how many times' asks for ratio, 'altogether' asks for total.

difference = larger - smaller; total = sum of all; ratio = A/B

Difference: Max value 80, Min value 30 → Difference = 50
Total: Values 20, 30, 40, 50 → Total = 140
Which is higher: Compare bar heights or values directly

How to recognize it

'How much more/less' → calculate difference
'What is the total' → add all values
'Which is greater' → direct comparison
'Range' → max minus min

Common mistakes

Subtracting in wrong order (gives negative difference)
Missing values when calculating totals
Comparing without reading exact values first

Step-by-step walkthrough

Using the bar chart, how much more is the highest value than the lowest?

Scan all bars to find the minimum value: Q2 = 30 (shortest bar)
Scan all bars to find the maximum value: Q1 = 80 (tallest bar)
'How much more' means we need the difference (subtraction)
Calculate: 80 - 30 = 50

Answer: 50 more

Practice guidance

Data Interpretation