Question

What is the HCF of 1820 and 204?
(With explanation please)

Answer 1

4

Explanation:

Write down all the factors of both the numbers.

204- 1,2,3,4,6,12,17,34,51,68,102,204

1820- 1,2,4,5,7,10,13,14,20,26,28,35,52,65,

70,91,130,140,182,260.....

As we can see, the common factors of both the numbers are:

1,2,4

So the highest common factor is:

4

:)

Answer 2

4

Explanation:

• Divide the larger number by the smaller number

• If remainder is 0 then the smaller number is the HCF

• If not repeat with the remainder and smaller number until a remainder of 0 is reached.

1820 ÷ 204 = 8 remainder 188

204 ÷ 188 = 1 remainder 16

188 ÷ 16 = 11 remainder 12

16 ÷ 12 = 1 remainder 4

12 ÷ 4 = 3 remainder 0 ← remainder of 0 reached

Thus 4 is the HCF of 1820 and 204