The GCF is 30.
Hi!
Here is an easy method to find the HCF of absolutely any pair of numbers.
Step 1
Find the difference between the numbers.
x - y = z
Step 2
Ask this question, 'Is z a factor of x and y?'
Another way to ask this question is, 'Are x and y in z's timetable?'
If the answer is 'YES', then z is the HCF/ GCF.
It's as simple as that.
All you have to do is substitute the letters with the numbers that you were given in the question.
Let's take 9 & 12 as examples.
12 - 9 = 3
Is 3 a factor of 12 and 9? Yes
Are 12 and 9 in 3's timetable? Yes (3 x 3 = 9, 3 x 4 = 12)
HCF/ GCF = 3
According to your question, the numbers are 180 and 210.
210 - 180 = 30
Is 30 a factor of 210 and 180? Yes
Are 210 and 180 in 30's timetable? Yes (30 x 60 = 180, 30 x 70 = 210)
HCF/GCF = 30
DISCLAIMER: This only works on two numbers.
You can ask one question. It isn't necessary to ask both questions.
The HCF of 180 and 210 is 30.
30
2
It is 35
No. The prime factors of 140 are 2,2,5 and 7 The prime factors of 210 are 2,3,5 and 7 The common prime factors are 2,5 and 7 Thus the HCF is 2x5x7, or 70.
15 is the answer
3.
The HCF of 30 and 105 is 15.
The GCF is 30.
HCF = 14
HCF(210, 308) = 14.
HCF(96, 180) = 12
The GCF is 180.
It is: 180
The GCF is 42.
It is 35
The answer is 21
It is: 14
It is: 30
21