Integers in Other Places

Class 6 Maths · Chapter 10: The Other Side of Zero · NCERT Ganita Prakash section 10.3

Learn

Money. Kabir's school bank account has ₹200. He takes out ₹250 for a trip; the bank lets students borrow a little. His balance is now −₹50: he owes ₹50. Money put in is +, money taken out is −.

200 − 250 = −50

Temperature. Water freezes at 0 °C. In a mountain village on a winter night the thermometer can read −8 °C, 8 degrees below freezing. If it warms up by 11 degrees by noon, it becomes (−8) + 11 = +3 °C.

Heights. Heights are measured from sea level (0 m). A hilltop might be +900 m; the bottom of a lake or the sea can be −40 m. From −40 m up to +900 m is 900 − (−40) = 940 m.

900 − (−40) = 940

Games. In a quiz, a right answer scores +10 and a wrong one −5. Tenzin gets 3 right and 4 wrong: 30 + (−20) = +10. In football, a team that scored 2 and let in 5 has a goal difference of −3.

Explore: use the number line like a thermometer lying down.

1. It is −7 °C. Put the point there.
2. It was 3 °C and the temperature fell by 8 degrees. Show the new temperature.
3. A bank balance of −₹4 hundred gets +₹9 hundred. Show the new balance (in hundreds).

Remember

• Integers describe money in and out, temperatures below zero, heights below sea level, and scores.
• The distance between a positive and a negative number is found by subtracting: 900 − (−40) = 940.

Quick check

The temperature is −2 °C and it falls by 5 degrees. What is it now?

1. −7 °C
2. +3 °C
3. −3 °C
4. +7 °C

Think about it

Meher's bank balance is −₹30. Rohan's is −₹80. Who owes more money? Whose balance is greater?

Practice

Practise with fresh questions at three levels (easy, medium, hard), some answered hands-on, with hints and worked answers. Get 4 of your last 5 right to finish the topic.