Basic Facts-Level 3-4
Eleventh Heaven
You need
a classmate
a calculator (optional)
Activity
1.
11
a.
Multiply 15, 25, 35, and 45 by 11. (You can use your calculator for this.)
b.
With a classmate, look for a pattern in the equations.
to
wers his:
s
n
a
the
et
d out number lik
e
k
r
o
w
git
Toby
wo-di
t
twoa
a
s
e
e
m
i
t
m
o
Give umber t
n
.
digit ly by 11
ip
mult
OK
,t
???
s
dred
n
u
…
h
see
the
the
Let’s becomes ecomes
b
The 2 nd the 6 s 2_6.
a
t’
digit igit, so i
d
ones
ry
26
x
11
.
wh Yes,
ten at is but
s d the
igit
?
2?6
I add
,
t
i
s dig et 8.
n
e
t
g
e
et th the 6 to 6.
g
o
T
and er is 28
2
e
th
sw
e an
h
t
So
Hey, tha
t’s right
!
How did
2 + 6 = 8 know you
that?
2.
3.
4.
286
Use Toby’s method to answer:
a.
36 x 11
a.
How does this pattern work? Can you explain it?
b.
Are there two-digit numbers that this pattern will
not work for? Discuss this with a classmate.
b.
43 x 11
c.
52 x 11
Find ways to remember your “teen times tables”. For
example, how would you work out your 19 times table?
Exploring two-digit multiplication
3