The GCF is 1.
To make this easier, let's first factor 18 and 21 into their prime factors: 18=2*3^2 21=3*7 Now it's very easy to find the LCM and GCF. The LCM is 2*3^2*7=126, and the GCF is 3.
gcf(18, 21, 42) = 3. 18 = 2 x 3^2 21 = 3 x 7 24 = 2^3 x 3 hcf = 3
The greatest common factor (GCF) of 63, 21, and 7 is 7.
The GCF is 7.
GCF(14, 28, 21) = 7
The GCF is 7.
The GCF is 7.
The greatest common factor of the numbers 56 and 21 is 7.
The greatest, (Highest) Common Factor of 21 and 56 is 7
The GCF is 7.
The GCF is 7.
The GCF is 7.