Numbers and integers

Which of the following is a correct mathematical statement?

• -5 > 3

• 5 < -3

• 5 < 3

• -5 < -3

It was -8⁰C and now 2⁰C.

The temperature has _______________.

• risen 6⁰C

• fallen 6⁰C

• risen 10⁰C

• fallen 10⁰C

• 1.5

• 24

• −24

• −1.5

• −31

• 18

• −48

• 4

Which one of the following statements is correct?

• A prime number is one which can be divided only by itself.

• 1 is a prime number.

• Prime numbers are numbers which have exactly two factors.

• Every even number can be written as the sum of two prime numbers.

84 can be expressed as a product of its prime factors.

Which of the following shows the correct prime factorisation?

The H.C.F. and L.C.M. of two numbers are 72 and 432 respectively.

If one of the numbers is 144, what is the other number?

• 576

• 288

• 234

• 216

Two satellites at different heights above the earth take 16 hours and 18 hours respectively to complete one revolution around the earth.

At a certain instant, they were both exactly above Singapore.

When will they next be exactly above Singapore?

• 2 h

• 34 h

• 72 h

• 144 h

• 360

• 270

• 180

• 30