What is the HCF / GCF of 120, 180 and 190

3 answers

120 = 10 * 3 * 2 * 2
180 = 10 * 3 * 3 * 2
190 = 10 * 19

looks like 10
But the answer in the book is 6840 for HCF / GCF of 120, 180 and 190 calculated under prime factorisation method. How it is? Can someone explain the calculation in depth..!!
Sure, but that is the lowest common multiple

we need
one 10
one 19
two 2
two 3

10 * 19 * 2 * 2 * 3 * 3 = 6840