Your browser is out of date. Mathspace won't be able to function correctly.
Mathspace system requirements
×
Book a Demo
Topics
N
u
m
b
e
r
(
a
d
d
/
s
u
b
)
S
i
n
g
l
e
d
i
g
i
t
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
A
d
d
i
t
i
o
n
f
a
c
t
f
a
m
i
l
i
e
s
(
a
+
b
=
c
,
c
-
b
=
a
)
Lesson
Practice
F
a
c
t
F
a
m
i
l
i
e
s
(
I
n
v
e
s
t
i
g
a
t
i
o
n
)
R
e
p
r
e
s
e
n
t
a
t
i
o
n
o
f
a
d
d
/
s
u
b
u
s
i
n
g
o
b
j
e
c
t
s
S
t
r
a
t
e
g
y
-
B
r
i
d
g
e
t
o
1
0
(
s
i
n
g
l
e
a
n
d
t
w
o
d
i
g
i
t
)
S
t
r
a
t
e
g
y
-
C
o
m
p
e
n
s
a
t
i
o
n
(
s
i
n
g
l
e
a
n
d
t
w
o
d
i
g
i
t
)
S
t
r
a
t
e
g
y
-
N
u
m
b
e
r
l
i
n
e
(
s
i
n
g
l
e
a
n
d
t
w
o
d
i
g
i
t
)
U
s
e
s
t
r
a
t
e
g
i
e
s
t
o
a
d
d
/
s
u
b
t
r
a
c
t
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
W
o
r
d
s
e
n
t
e
n
c
e
s
f
o
r
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
U
s
e
s
t
r
a
t
e
g
i
e
s
t
o
a
d
d
/
s
u
b
t
r
a
c
t
a
c
r
o
s
s
t
h
e
1
0
0
C
o
n
n
e
c
t
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
A
d
d
m
u
l
t
i
p
l
e
s
o
f
1
0
'
s
t
o
s
i
n
g
l
e
d
i
g
i
t
n
u
m
b
e
r
s
A
d
d
m
u
l
t
i
p
l
e
s
o
f
1
0
'
s
t
o
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
S
u
b
t
r
a
c
t
m
u
l
t
i
p
l
e
s
o
f
1
0
'
s
f
r
o
m
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
P
a
t
t
e
r
n
s
i
n
a
d
d
i
t
i
o
n
I
P
a
t
t
e
r
n
s
i
n
a
d
d
i
t
i
o
n
I
I
P
a
t
t
e
r
n
s
i
n
s
u
b
t
r
a
c
t
i
o
n
I
P
a
t
t
e
r
n
s
i
n
s
u
b
t
r
a
c
t
i
o
n
I
I
C
o
m
p
l
e
t
e
s
t
a
t
e
m
e
n
t
s
t
o
m
a
k
e
a
t
a
r
g
e
t
n
u
m
b
e
r
u
p
t
o
2
0
A
d
d
m
i
s
s
i
n
g
e
l
e
m
e
n
t
s
t
o
m
a
k
e
a
s
t
a
t
e
m
e
n
t
t
r
u
e
w
i
t
h
t
o
t
a
l
s
u
p
t
o
2
0
A
d
d
3
n
u
m
b
e
r
s
(
m
i
x
o
f
s
i
n
g
l
e
o
r
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
)
I
W
o
r
d
p
r
o
b
l
e
m
s
I
A
d
d
m
u
l
t
i
p
l
e
s
o
f
1
0
0
'
s
t
o
s
i
n
g
l
e
d
i
g
i
t
n
u
m
b
e
r
s
A
d
d
m
u
l
t
i
p
l
e
s
o
f
1
0
0
'
s
t
o
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
S
u
b
t
r
a
c
t
m
u
l
t
i
p
l
e
s
o
f
1
0
0
'
s
f
r
o
m
t
h
r
e
e
d
i
g
i
t
n
u
m
b
e
r
s
P
a
t
t
e
r
n
s
i
n
a
d
d
i
t
i
o
n
I
I
I
P
a
t
t
e
r
n
s
i
n
s
u
b
t
r
a
c
t
i
o
n
I
I
I
C
o
m
p
l
e
t
e
s
t
a
t
e
m
e
n
t
s
t
o
m
a
k
e
a
t
a
r
g
e
t
n
u
m
b
e
r
u
p
t
o
5
0
A
d
d
m
i
s
s
i
n
g
e
l
e
m
e
n
t
s
t
o
m
a
k
e
a
s
t
a
t
e
m
e
n
t
t
r
u
e
w
i
t
h
t
o
t
a
l
s
u
p
t
o
5
0
I
n
e
q
u
a
l
i
t
i
e
s
w
i
t
h
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
s
t
a
t
e
m
e
n
t
s
A
d
d
3
n
u
m
b
e
r
s
(
m
i
x
o
f
s
i
n
g
l
e
o
r
t
w
o
d
i
g
i
t
n
u
m
b
e
r
s
)
I
I
A
d
d
a
n
d
s
u
b
t
r
a
c
t
t
h
r
e
e
d
i
g
i
t
n
u
m
b
e
r
s
I
A
d
d
a
n
d
s
u
b
t
r
a
c
t
t
h
r
e
e
d
i
g
i
t
n
u
m
b
e
r
s
I
I
A
d
d
a
n
d
s
u
b
t
r
a
c
t
f
o
u
r
d
i
g
i
t
n
u
m
b
e
r
s
I
A
d
d
a
n
d
s
u
b
t
r
a
c
t
f
o
u
r
d
i
g
i
t
n
u
m
b
e
r
s
I
I
W
o
r
d
p
r
o
b
l
e
m
s
I
I
U
s
e
r
o
u
n
d
i
n
g
t
o
e
s
t
i
m
a
t
e
s
o
l
u
t
i
o
n
s
f
o
r
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
P
a
t
t
e
r
n
s
i
n
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
I
P
a
t
t
e
r
n
s
i
n
a
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
I
I
C
o
m
p
l
e
t
e
s
t
a
t
e
m
e
n
t
s
t
o
m
a
k
e
a
t
a
r
g
e
t
n
u
m
b
e
r
u
p
t
o
1
0
0
A
d
d
3
n
u
m
b
e
r
s
(
m
i
x
o
f
s
i
n
g
l
e
,
t
w
o
a
n
d
t
h
r
e
e
d
i
g
i
t
n
u
m
b
e
r
s
)
A
d
d
a
n
d
s
u
b
t
r
a
c
t
l
a
r
g
e
n
u
m
b
e
r
s
I
A
d
d
a
n
d
s
u
b
t
r
a
c
t
l
a
r
g
e
n
u
m
b
e
r
s
I
I
W
o
r
d
p
r
o
b
l
e
m
s
I
I
I
A
d
d
i
t
i
o
n
a
n
d
s
u
b
t
r
a
c
t
i
o
n
p
r
o
b
l
e
m
s
i
n
v
o
l
v
i
n
g
a
n
g
l
e
s
M
i
x
e
d
a
d
d
i
t
i
o
n
s
M
i
x
e
d
s
u
b
t
r
a
c
t
i
o
n
s
W
o
r
d
p
r
o
b
l
e
m
s
I
V
A
d
d
i
t
i
o
n
a
n
d
S
u
b
t
r
a
c
t
i
o
n
w
i
t
h
a
n
A
b
a
c
u
s
(
I
n
v
e
s
t
i
g
a
t
i
o
n
)
Log in
Sign up
Book a Demo
United Kingdom
United Kingdom
Primary
Addition fact families (a+b=c, c-b=a)
Loading...
