The Other Side of Zero — Quiz

Q1. The chapter says the picture showing 0, 1, 2, 3, … extending only to the right of 0 is actually a number 'ray', not a number line. Why?

• A. Because it has dots between the numbers.
• B. Because it starts at 0 and goes forever only to the right, but not to the left.
• C. Because it does not contain fractions.
• D. Because it has arrows on both ends.

Q2. Standing on the ground floor of Bela's Building of Fun, Ravi wants to reach a floor four levels above. What should he press?

• A. '+' four times, written as +4.
• B. '−' four times, written as −4.
• C. '+' twice then '−' twice.
• D. Nothing; the lift moves by itself.

Q3. Priya writes '+0' for the ground floor in her notebook. According to the chapter, is this correct?

• A. Yes, because every floor needs a sign.
• B. Yes, because 0 is a positive number.
• C. No; we do not put a + or − sign in front of 0.
• D. No; the correct form is '−0'.

Q4. On the integer number line, positive numbers are usually written as 1, 2, 3 rather than +1, +2, +3. The reason is

• A. Positive numbers do not really need a sign — the '+' is dropped by convention.
• B. Positive numbers are less important than negative numbers.
• C. The '+' sign means addition, not a positive number.
• D. The '+' sign is reserved for the lift button.

Q5. Using Starting Floor + Movement = Target Floor, evaluate (+1) + (+4).

• A. +3
• B. −3
• C. −5
• D. +5

Q6. Using the Building of Fun, evaluate (−1) + (+2).

• A. −3
• B. −1
• C. +1
• D. +3

Q7. Gurmit was in the Toy Store and wanted to go down two floors, but by mistake he pressed '+' two times. He then pressed '−' three times. Where does he end up, relative to the Toy Store?

• A. Two floors above.
• B. Two floors below.
• C. One floor below.
• D. One floor above.

Q8. What is the additive inverse of 0?

• A. +1
• B. −1
• C. 0 itself.
• D. 0 has no additive inverse.

Q9. Which is correct: −3 < −4 or −4 < −3?

• A. −3 < −4, because 3 is smaller than 4.
• B. Both are equal: −3 = −4.
• C. Neither; you cannot compare negative numbers.
• D. −4 < −3, because Floor −4 is lower than Floor −3.

Q10. Fill in the blank with < or >: 0 ___ −4.

• A. 0 < −4
• B. 0 > −4
• C. 0 = −4
• D. 0 ≥ −4 only sometimes.

Q11. Your starting floor is the Art Centre (+2) and your target floor is the Sports Centre (+5). What button press is needed?

• A. −3.
• B. −7.
• C. +7.
• D. +3.

Q12. In the token model, what does a red token represent?

• A. A positive token, worth +1.
• B. A negative token, worth −1.
• C. A token that has no value.
• D. A pair of zero tokens.

Q13. In a bank passbook, the chapter tells us to think of

• A. Credits as negative numbers and debits as positive numbers.
• B. Credits as positive numbers and debits as negative numbers.
• C. Both credits and debits as positive numbers.
• D. Both as negative numbers.

Q14. In a geographical cross section, which height is marked as 0 m?

• A. The top of the highest mountain.
• B. Sea level.
• C. The deepest point of the ocean.
• D. The centre of the Earth.

Q15. Which ancient Indian text, written around 300 BCE, wrote extensively about credit and debit and recognised that an account balance could be negative?

• A. Aryabhatiya by Aryabhata.
• B. Lilavati by Bhaskaracharya.
• C. Brahma-sphuta-siddhanta by Brahmagupta.
• D. Arthashastra by Kautilya.