WOLFRAM
|
DEMONSTRATIONS PROJECT
Trick to Multiply by
N
-1 in Base
N
b
a
s
e
N
6
7
8
9
1
0
(
N
-
1
)
×
1
2
3
4
5
6
7
8
9
9
×
5
=
4
5
i
n
b
a
s
e
1
0
I
n
b
a
s
e
1
0
,
m
u
l
t
i
p
l
y
i
n
g
d
i
g
i
t
s
b
y
9
p
r
o
d
u
c
e
s
a
n
i
c
e
p
a
t
t
e
r
n
.
T
h
i
s
D
e
m
o
n
s
t
r
a
t
i
o
n
e
x
t
e
n
d
s
t
h
e
t
r
i
c
k
,
s
h
o
w
i
n
g
a
s
i
m
p
l
e
w
a
y
t
o
m
u
l
t
i
p
l
y
b
y
N
-
1
i
n
b
a
s
e
N
.
