Textbook p9 #25: The three factors are 891, 539 and 2673.

The Prime factorisation of a number is 2^4 X 3^5 X 7^2 X 11.

Write down 3 factors of the number that are greater than 100.

(Hint: 16 X 11 = 176, which is a factor.)

16=2x2x2x2

15=3x3x3x3x3

49=7x7

3x3x3x3x11=891

7x7x11=539

3x3x3x3x3x11=2673

Textbook p9 #26:

The Prime factorisation of two numbers are 2 X 3^2 X 7^3 X 13 and 3 X 7^2 X 13^3 X 17 .

Write down 3 common factors of the numbers.

The three common factors are 2, 3 and 13.

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Cheng Ngee

ReplyDeleteTextbook p9 #25:

Note there's mistake in one of the lines

3^5 = 3x3x3x3x3 = 245

Indeed, the 3 answers you submitted are correct :D

Textbook p9 #26:

Could you elaborate how you arrive at the 3 numbers (2, 3 and 13)?

Indeed, amongst the 3 numbers you submitted, only "3" and "13" are correct whereas "2" is not the answer.

Do you have any idea why?

Could you suggest another common factor?