Week 2 Revision Quiz

Grace and Leo are discussing prime numbers. Select the first 3 prime numbers after 20

• 21, 23, 25

• 21, 27, 30

• 25, 29, 31

• 23, 29, 31

• 27, 29, 37

Answer explanation

The first 3 prime numbers after 20 are 23, 29, and 31. Therefore, the correct answer is 23, 29, 31.

Aarav is collecting multiples of 13. Which of the following sets contains three multiples of 13?

• 26, 39, 44

• 25, 42, 55

• 26, 39, 52

• 13, 26, 32

Answer explanation

The correct multiples of 13 are 26, 39, and 42, which are found in the answer choice '26, 39, 42'.

Round 136.7891 to 2 decimal places

Mathematical Equivalence

ON

Answer explanation

You need 2 digits after the decimal point. Look at the third digit to see if you need to round up. Remember if the 3rd digit is 5 or more we round the number to the left up by one, otherwise, we throw the third digit away.

Estimate 27.90 multiplied by 8

Mathematical Equivalence

ON

Answer explanation

First, make the decimal number into a whole number by multiplying by a factor of 10 or 100.

2790 x 8

8 x 0 = 8

90 x 8 = 720

700 x 8 = 5600

2000 x 8 = 16000

Next, add all the values together.

Finally, put the decimal point back in. Count the number of digits after the decimal point in the original calculation and move the decimal point that number of places to the left starting from the far right.

Multiply 17 by 12

Mathematical Equivalence

ON

Answer explanation

Multiply 17 by 2 and then by 10. Add the two answers together.

Round 78.0446 to 1 decimal place

Mathematical Equivalence

ON

Answer explanation

In this question, you use all the digits after the decimal point. The last 6 influences all the other values rounding all up by 1.

Divide 160 by 5

Mathematical Equivalence

ON

Answer explanation

use the bus stop method to calculate the answer

Starting from the left divide 1 by 5, in this instance, it does not go so we move the one across to make 16, divide 16 by 5 to get three, and move any remainder across onto the next digit to make 10. Divide 10 by 5 to get 2

You take red and blue tablets daily. If you take a blue tablet every 3 hours and a red tablet every 4 hours. If you take both tablets together when you get up in the morning at 8 am when will you take them both together again?

Mathematical Equivalence

ON

Answer explanation

Starting at 8 am keep adding 3 hours to the time now do the same for 4 hours. When you see the same time in both sequences is when you take the tablets again at the same time.

Multiply 567 by 23

Mathematical Equivalence

ON

Answer explanation

Refer back to an earlier explanation

Divide 2456 by 7

Mathematical Equivalence

ON

Answer explanation

Refer back to an earlier explanation.