The Least Common Multiple (LCM) of (7,9,10) is 630.
119
280
420
Which you don't want. You want the least common denominator, which is 360.
The least common multiple of 7 , 8 , 10 , 12 = 840
The Least Common Multiple (LCM) of (7,9,10) is 630.
42
It is: 91
14
84
28
28
It is 70
Their product.
84
119