Illustrate the Least Common Multiple
Python 3, 80 bytes
Saved 1 byte thanks to Halvard Hummel and 1 byte thanks to Jonathan Allan.
import math
def f(*l):
 for k in 0,1:print(l[~k]//math.gcd(*l)*(~-l[k]*&quot;-&quot;+&quot;|&quot;))

Test it online!
lambda*l:&quot;\n&quot;.join(l[0]*l[1]//math.gcd(*l)//k*(~-k*&quot;-&quot;+&quot;|&quot;)for k in l)
import math

Test it online! (82 bytes - initial answer)
This is the best I could do in Python 2 (81 bytes). It seems like I cannot comment on that answer, I'll just post this here instead:
from fractions import*
l=a,b=input()
for k in l:print a*b/gcd(*l)/k*(~-k*&quot;-&quot;+&quot;|&quot;)

Test it online!
First attempt here, probably sub-optimal!