Tag: concept of directed numbers and number line

Questions Related to concept of directed numbers and number line

A driver is $20$ m below sea level. If he goes further down by $10$m, then find his new position.

maths concept of directed numbers and number line subtraction of directed numbers subtraction of integers subtraction of integers on number line

  1. $10$m

  2. $-10$m

  3. $30$m

  4. $-30$m

Show answer
Correct Option: D
Explanation:

Sea Level $\rightarrow$ $0$m

Original Position $\rightarrow$ $-20$m (Since he is below sea level)
New Position $\rightarrow$ $-$ ($20+10$) $\rightarrow$ $-30$m


$0$ is the __________ identify for whole numbers, whereas $1$ is the ___________ identify for whole numbers.

maths concept of directed numbers and number line subtraction of directed numbers subtraction of integers subtraction of integers on number line

  1. Additive, Multiplicative

  2. Multiplicative, Additive

  3. Commutative, Additive

  4. Positive, Not-defined

Show answer
Correct Option: A
Explanation:

When $0$ is added to any given whole number, the resultant number is the given whole number itself. This shows that $0$ is additive identity for whole number.

When $1$ is multiplied to any whole number, the resultant number is the number itself.
Here $0$ and $1$ are not making any change to the number.
Hence option A is correct.

On a hill, the temperature at $8$ p.m. was $2^o$C but at the mid-night of the same day, it fell down to $-3^o$C. By how many degrees did the temperature fall?

maths concept of directed numbers and number line subtraction of directed numbers subtraction of integers subtraction of integers on number line

  1. $6^o$C

  2. $5^o$C

  3. $2^o$C

  4. $3^o$C

Show answer
Correct Option: B
Explanation:

Temperature difference $\rightarrow$ Temperature at midnight $-$ Temperature at 8p.m.

Temperature difference $\rightarrow$ ($-3$) $-$ ($2$) $\rightarrow$ $-5$
Temperature fall by 5 degree.
Hemce Option B is correct.