14

© H

arpe

rCol

linsP

ublis

hers

201

6

Nam

e:

Volu

me

1

Dat

e:

THE M

aths

Hera

ldCN

PM

Nam

e:

S&C

Vol

ume

3

Dat

e:

The

Mat

hs H

eral

dIs

sue

9 -

Mul

tiplic

atio

nIs

sue

9 -

Mul

tiplic

atio

n

The

Puzz

ler

Mon

ey

Mat

ters

The

Puzz

ler

4 8

9

12

16

18

21

24

35

40

45

Writ

e th

e di

gits

1 t

o 9

on t

he 3

× 3

grid

so

that

pa

irs o

f ad

jace

nt d

igits

, bot

h ho

rizon

tally

and

ve

rtic

ally

, mak

e on

ly t

he p

rodu

cts

abov

e.

For

exam

ple:

Sinb

ad f

ound

a m

agic

cas

ket.

W

hate

ver

was

left

in it

ove

rnig

ht

wou

ld b

e do

uble

d by

the

nex

t m

orni

ng.

Sinb

ad p

ut a

gol

d co

in in

the

cask

et

and

left

it a

lone

. Aft

er 2

wee

ks th

e ca

sket

was

full

of g

old

coin

s.

Aft

er h

ow lo

ng w

as t

he c

aske

t ha

lf fu

ll of

gol

d co

ins?

Look

at

the

mul

tiplic

atio

n ca

lcul

atio

n on

the

rig

ht.

The

answ

er h

as b

een

wor

ked

out

usin

g 2

diff

eren

t m

etho

ds.

How

man

y di

ffer

ent

met

hods

ca

n yo

u us

e to

wor

k ou

t th

e an

swer

to

this

mul

tiplic

atio

n ca

lcul

atio

n? 1

72 ×

4

Sinb

ad h

as a

mag

ic c

aske

t.

Wha

teve

r is

left

in it

ove

rnig

ht is

do

uble

d by

the

nex

t m

orni

ng.

Sinb

ad le

t hi

s fr

iend

Ahm

ed u

se

it, b

ut c

harg

ed h

im 6

gol

d co

ins

each

nig

ht b

efor

e he

let

him

put

an

ythi

ng in

to it

. A

fter

usi

ng it

for

6 n

ight

s,

Ahm

ed f

ound

tha

t he

had

the

sa

me

num

ber

of g

old

coin

s as

he

star

ted

with

. H

ow m

any

gold

coi

ns d

id A

hmed

st

art

with

?Th

e Bi

g R

ead

Book

shop

op

ens

its d

oors

at

9 o’

cloc

k.

In t

he fi

rst

hour

the

y ta

ke £

10.

In e

very

hou

r af

ter

that

, th

ey t

ake

twic

e as

muc

h as

the

ho

ur b

efor

e.H

ow m

uch

mon

ey w

ill t

hey

take

be

twee

n 4

o’cl

ock

and

5 o’

cloc

k?If

the

sho

p cl

oses

at

6 o’

cloc

k, h

ow m

uch

mon

ey w

ill t

hey

have

tak

en d

urin

g th

e en

tire

day?

3 ×

CAT

= A

AA

Each

of

the

lett

ers

stan

ds

for

a di

ffer

ent

digi

t.

Whi

ch d

igit

does

eac

h st

and

for?

Expl

ain

how

you

wor

ked

out

wha

t ea

ch le

tter

st

ands

for

.

Prod

uct

of 1

8Pr

oduc

t of

24

6 38

3

The

Lang

uage

of

Mat

hsW

hat’s

th

e Pr

oble

m?

Let’s

Inve

stig

ate

25 ×

9

20

5

9 18

0 45

=

225

(20

× 9

)(

5 ×

9)

25×

9 180 45 225

1

scal

ing

67325_P023-042.indd 3967325_P023-042.indd 39 28/03/16 11:51 AM28/03/16 11:51 AM

32

© H

arperCollinsPublishers 2016

Issue 9 - Multiplication

Issue 9 - Multiplication

The Puzzler

What’s the Problem

?

Thinking of all the answers to the

multiplication facts for the 3, 4,

5, 8 and 10 multiplication tables,

which of the 6 boxes on this

diagram do you think w

ill have the m

ost numbers in it?

Which box do you think w

ill have few

est numbers?

Once you’ve m

ade your predictions, w

rite all the answers

to the multiplication facts for the

3, 4, 5, 8 and 10 multiplication

tables on this diagram.

Were your predictions correct?

Investigate the following m

ethod of working

out the multiplication facts from

6 × 6 to

9 × 9, using the fi ngers of both hands.

To use this method, you m

ust know by heart

the 2, 3, 4 and 5 multiplication facts.

Assign the num

bers 6 to 10 to the digits of each fi nger, starting from

the little fi nger (6) to the thumb (10).

Investigate using this method for other m

ultiplication facts from

6 × 6 to 9 ×

9.W

rite what you think about this m

ethod. W

hat are its strengths? W

hat are its limitations?

Example 1: 6 ×

8•

Touch the “6 fi nger” with the

“8 fi nger”. •

Add together the fi ngers

touching and the fi ngers below

the touching fi ngers (2 + 2 =

4).•

Multiply this total by 10

(4 × 10 =

40).•

Multiply the fi ngers above the

“touch” on your left hand by the fi ngers above the “touch” on your right hand (4 ×

2 = 8).

• A

dd the two answ

ers together (40 +

8 = 48).

• So, 6 ×

8 = 48.

Example 2: 7 ×

9•

Touch the “7 fi nger” with the

“9 fi nger”. •

Add together the fi ngers

touching and the fi ngers below

the touching fi ngers (2 + 4 =

6).•

Multiply this total by 10

(6 × 10 =

60).•

Multiply the fi ngers above the

“touch” on your left hand by the fi ngers above the “touch” on your right hand (3 ×

1 = 3).

• A

dd the two answ

ers together (60 +

3 = 63).

• So, 7 ×

9 = 63.

Bridget lives on a farm.

This is part of an email she sent to

her cousin in New

Zealand.H

ow m

any sheep are there on the farm

?H

ow m

any chickens are there?H

ow did you w

ork out how m

any of each anim

al there are?

Multiple of 8

Multiple of 10

Multiple of 3Multiple of 4Multiple of 5

Let’s Investigate

6 8

+

7 9

+

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