Question 1062526
Doing only #1.


4 and 5 have product of 20.
{{{4*5=20}}}, their Lowest and "first" multiple is 20.


{{{1*20=20}}}
'
{{{2*20=40}}}
'
{{{3*20=60}}}
'
{{{4*20=80}}}
'
{{{5*20=100}}}

.
.
{{{8*20=160}}}---------their eighth common multiple