What is the HCF / GCF of 120, 180 and 190 as per prime factorisation. Please explain in depth....
120 = 2^3 3 5
180 = 2^2 3^2 5
190 = 2 5 19
So, take the highest power of each prime common to all numbers:
2 5 = 10
No other (larger) combination of those prime factors will divide all three numbers.