a:6=5 rest 0
a=5×6+0
a=30+0
a=30
b:6=5 rest 1
b=5×6+1
b=30+1
b=31
c:6=5 rest 2
c=5×6+2
c=30+2
c=32
d:6=5 rest 3
d=5×6+3
d=30+3
d=33
e:6=5 rest 4
e=5×6+4
e=30+4
e=34
f:6=5 rest 5
f=5×6+5
f=30+5
f=35
30+31+32+33+34+35=
61+32+33+34+35=
93+33+34+35=
126+34+35=
160+35=195
