Find The GCF of 16 and 80, 32 and 51, 21 and 44, 12 and 80, 8 and 36, 16 and 140, 12 and 76, 24 and 30,?

Question

pls help me pls... give me the best explanation pls

Answer 1

The GCF is the highest factor of both numbers.

For instance, 16 and 80 is 8, because 8 goes into both 16 and 80 and no number greater than it also does.

32 and 51, 51 is prime, thus the GCF is 1.

21 and 44 is also 1, since the only other factors of 21 are 7 and 3, and neither go into 44.

12 and 80, factors of 12 are 6, 4, 3, 1, 4 is the only one that also goes into 80.

8 and 36 is 4

16 and 140 is... 4
12 and 76 is also 4 lol
24 and 30 is 6.

Answer 2

16 and 80 : 8 (factorize 16, and test all the factors on 80, one by one)
32 and 51 : 1 (51 is prime)
21 and 44 : 1 (21's factors are 3 and 7, that don't factorize 44)
12 and 80 : 4
8 and 36 : 4
16 and 140 : 4
12 and 76 : 4
24 and 30 : 6

Answer 3

You can factor these numbers completely and then select all the factors the numbers have in common. Combine those for the greatest common factor.

16=2*2*2*2
80=2*2*2*2*5
These number have four 2s as factors.
2*2*2*2=16, so 16 is the GCF. (16*5=80)

32=2*2*2*2*2
51=3*17
These numbers don't share any common factors in these lists, but all numbers have 1 as a factor, so GCF=1.

21=3*7
44=2*2*11
GCF=1 because there are no other factors in common.

12=2*2*3
80=2*2*2*2*5
These number share two 2s and that's all.
GCF=2*2=4

Do the rest of these in the same manner.

Answer 4

The first respondant had the right definition, but his example is not correct. 16 divides both 16 and 80 and the dividend is an integrer, so 16 is the GCF. For 32 and 51, if you list the factors for each, (2,4,8,16 and 3,17), there is no GCF (except 1, but who cares?).

Answer 5

I recomend that you use factor trees.

~Kuh-laire~