Maths

1)6
2)12
3)4
4)46


2012-08-22 16:25:46 補充：
To 梁婉玲 ：你在第四題中所寫的答案錯了！

2012-08-23 18:36:24 補充：
To Godfrey : you don't need to afraid of me = =

Find HCF

3)24,30
2 )8, 10
4, 5

HCF of 24 and 30 = 3 x 2 = 6 (answer)


12)36,84
3, 7

HCF of 36 and 84 = 12 (answer)


4)16,20,24
4, 5, 6

HCF of 16, 20 and 24 = 4 (answer)


23 )92,138,230
2 )4, 6, 10
2, 3, 5

HCF of 92, 138 and 230 = 23 x 2 = 46 (answer)

The factors of 92 = 1, 2, 4, 23, 46, 92
The factors of 138 = 1, 2, 3, 6, 23, 46, 69, 138
The factors of 230 = 1, 2, 5, 23, 46, 69, 115, 230

46 is the highest common factor of 92, 138 and 230

23 is not the highest common factor.
92 = 46 x 2
138 = 46 x 3
230 = 46 x 5

92, 138 and 230 are divisible by 46, without remainder.
46 should be the HCF.

I am afraid that only 回答者: Knowledge Plus gets it right.