Drawing a bar graph

Steps to draw a bar graph:

• Draw a horizontal line and a vertical line.
• Along the horizontal line, write the categories, equally spaced.
• Choose a scale for the vertical line so the tallest bar fits your paper, and mark it from zero in equal steps.
• Draw bars of the same width with the same gap between them. A light dotted line up from each category helps keep the bar straight, and if a value is zero, leave its gap empty.

For Shri Nilesh's sweets (jalebi 6, gulab jamun 9, gujiya 13, barfi 3, rasgulla 7), 1 unit = 1 student works well: the jalebi bar is 6 units tall. But Smriti's runs in 8 matches go up to 100, so the book uses 1 unit = 10 runs: her 80 runs make a bar 8 units tall.

Imran's family spends ₹3000 on house rent, ₹3400 on food, ₹800 on education, ₹400 on electricity, ₹600 on transport and ₹1200 on other things. With 1 unit = ₹200, each height is the amount ÷ the scale: rent 3000 ÷ 200 = 15 units, food 3400 ÷ 200 = 17, education 4, electricity 2, transport 3, others 6.

We can also work backwards. Pooja's bar graph of tickets sold at Bhopal station was partly erased. The Vidisha bar is 6 units for 24 tickets, so 1 unit = 24 ÷ 6 = 4 tickets. Then Indore's 28 tickets need 28 ÷ 4 = 7 units. A bar that is not the right height for its number is drawn wrongly, and a scale that does not start from zero makes every bar misleading.