Answer:
42
Step-by-step explanation:
When calculating the greatest common divisor, you must look for the smallest divisors that can divide the no. s given simultaneously.
So in this case the smallest divisor will be 2.
378 =189. 420 =210
2. 2
The next divisor that 189 and 210 can both be divided with is 3
189 =63. 210 =70
3. 3
The third smallest divisor that can 63 and 70 can be divided with is 7
63 =9. 70 =10
7. 7
9 and 10 have no common divisors that can divide them fully without leaving a remainder
So to get the greatest common divisor, multiply all the divisors you have used
In this case we've used 2,3,7
2x3x7= 42
