Data Handling (NCERT Ch. 9)

• Collect and organise data using tally marks and frequency tables.
• Read and interpret pictographs (data shown using symbols/pictures).
• Read, interpret, and draw simple bar graphs.

1. Data is a collection of numbers/facts gathered for a specific purpose.
2. Tally marks record data in groups of 5 (four vertical strokes + one diagonal strike).
3. A frequency table shows how many times each value occurs.
4. A pictograph uses repeated symbols to represent data, with each symbol standing for a fixed quantity (the scale/key).
5. A bar graph uses bars of uniform width, with height/length proportional to the value, to compare data visually.

In a pictograph, 🍎 = 10 apples. If a row shows 3 🍎 symbols, how many apples does it represent?

3 symbols x 10 apples/symbol = 30 apples.

• Forgetting to check the scale/key before reading a pictograph or bar graph.
• Drawing bars of unequal width, which makes the graph hard to compare.
• Miscounting tally marks (each group of 5 is 4 strokes + 1 diagonal).

• If a bar graph shows a bar of height 40 for "Mangoes" and the scale is 1 unit = 5 fruits, how many mangoes are there?
• Draw a tally mark for the number 7.

Open the Practice tab for graded questions on Data Handling (NCERT Ch. 9).