- First notions of PGCD (3 exercices)
- Euclid's Algorithm: GCD (8 exercices)
- Euclid's Algorithm: Coprime Numbers (3 exercices)
- Euclid's Algorithm: GCD and Modeling (14 exercices)
- PPCM (2 exercices)
- Us-math : GCF (1 exercice)
123456ABC21612690543618126903636181890365418180
DividendeDiviseurReste24036.....................×240...36...×............×............
E.6297
Here’s
a
spreadsheet
obtained
using
a
spreadsheet
program.
In
this
exercise,
we
try
to
understand
how
this
sheet
was
filled
in.
1
Looking
at
the
values
in
the
table,
sug-gest
a
formula
to
enter
in
cell
C1
,
then
copy
down.
2
In
this
question,
all
traces
of
re-search
will
be
left
on
the
copy.
They
will
be
valued.
The
spreadsheet
provides
two
functions
MAX
and
MIN
.
From
two
numbers,
MAX
returns
the
larger
value
and
MIN
the
smaller.
(example
MAX(23;12)=23
)
.
Which
formula
was
entered
in
cell
A2
,
then
copied
down?
2
What
does
the
number
in
cell
C5
represent,
in
relation
to
the
numbers
216
and
126
?
3
Is
the
fraction
216
126
irreducible?
If
not,
make
it
irreducible
by
detailing
the
calculations.
3.
Euclid’s
Algorithm:
Coprime
Numbers
E.616
1
Calculate
the
PGCD
of
the
integers
1183
and
455
,
spec-ifying
the
method
used.
2
Write
in
irreducible
form
the
fraction
1183
455
(Details
of
calculations
should
be
given)
E.646
1
Are
the
integers
2464
and
924
prime
with
each
other?
Justify.
2
Calculate
the
PGCD
of
2464
and
924
.
3
Give
the
sum
2464
924
+
5
6
as
an
irreducible
fraction
E.5181
Here
are
the
answers
proposed
by
a
student
to
an
exercise.
For
each
answer,
explain
why
it
is
correct
or
incorrect.
1
x
2
−
81
=
(
x
−
9)
2
2
(
x
−
3)(
x
+
5)
=
(
x
+
1)
2
−
16
3
The
integers
735
and
674
are
prime
to
each
other.
4.
Euclid’s
Algorithm:
GCD
and
Modeling
E.643
A
florist
has
240
tulips
and
36
orchids.
He
wants
to
use
all
the
flowers
in
his
possession
to
make
as
many
bouquets
as
possible,
each
containing
the
same
number
of
tulips
and
the
same
number
of
orchids.
1
We
note
:
k
:
the
number
of
bouquets
made.
x
:
the
number
of
tulips
making
up
each
bouquet.
y
:
the
number
of
orchids
making
up
each
bouquet.
Write
the
integers
240
and
36
using
k
,
x
and
y
.
2
What
does
the
integer
k
represent
for
the
two
integers
240
and
36
.
Specify.
3
Apply
Euclid’s
algorithm
to
the
following
integers
240
and
36
:
4
Specify
the
number
of
bouquets
the
florist
will
be
able
to
make
and
the
number
of
orchids
and
tulips
included
in
each.
https://chingmath.fr
chapExoCorrec/6297
sacados/6297
123456ABC21612690543618126903636181890365418180
chapExoCorrec/616
sacados/616
Groupe Nord - Juin 2003 - 2 points
chapExoCorrec/646
sacados/646
chapExoCorrec/5181
sacados/5181
chapExoCorrec/643
sacados/643
DividendeDiviseurReste24036.....................×240...36...×............×............
DividendeDiviseurReste24832.....................×248...32...×............×............
E.603
A
shopkeeper
has
248
strawberry
candies
and
32
mint
can-dies.
He
wants
to
make
as
many
packages
of
strawberry
candies
and
mint
candies
as
possible.
He
wants
to
use
all
the
candies
he
has,
and
each
package
must
contain
the
same
number
of
candies.
To
solve
this
problem,
complete
the
following
exercise:
Let’s
use
the
following
notation
:
k
:
le
nombre
de
bonbons
dans
chaque
paquet
x
:
le
nombre
de
paquets
à
la
fraise
y
:
le
nombre
de
paquets
à
la
menthe
We
have
the
following
relationships
in
terms
of
k
,
x
,
and
y
:
248
=
:
:
:
:
:
:
×
:
:
:
:
:
:
;
32
=
:
:
:
:
:
:
×
:
:
:
:
:
:
The
integer
:
:
:
:
:
:
is
therefore
a
divisor
of
the
integers
248
and
32
:
since
he
wants
to
make
as
many
packages
as
possible,
this
number
is
.
.
.
.
.
.
of
248
and
32
.
According
to
Euclid’s
algorithm,
we
have
:
From
this,
we
deduce
:
PGCD
(248
;
32)
=
:
:
:
:
:
:
We
have
the
following
two
calculations
:
248
:
:
:
:
:
:
=
:
:
:
:
:
:
;
32
:
:
:
:
:
:
=
:
:
:
:
:
:
Thus,
the
shopkeeper
will
prepare
:
:
:
:
:
:
strawberry-flavored
packages
and
:
:
:
:
:
:
mint-flavored
packages,
each
containing
:
:
:
:
:
:
pieces
of
candy.
E.3550
1
Are
the
integers
198
and
144
prime
with
each
other?
Jus-tify
the
answer
without
doing
any
calculation
.
2
Calculate
the
PGCD
of
198
and
144
detailing
the
method.
3
Write
the
fraction
144
198
in
irreducible
form.
Explain
the
method.
4
On
the
market,
a
producer
has
198
zucchinis
and
144
eggplants.
With
all
the
vegetables,
he
makes
trays
all
composed
identically.
He
uses
as
many
trays
as
possible.
a
How
many
trays
does
he
use?
b
How
many
zucchinis
and
eggplants
does
each
tray
con-tain?
E.3545
1
Determine
the
PGCD
of
1
394
and
255
.
2
A
craftsman
has
1
394
acai
seeds
and
255
peach
palm
seeds.
He
wants
to
make
identical
necklaces,
i.e.
each
contain-ing
the
same
number
of
acai
seeds
and
the
same
number
of
peach
palm
seeds.
a
How
many
necklaces
at
most
can
he
make
using
all
his
seeds?
b
In
this
case,
how
many
acai
seeds
and
peach
palm
seeds
does
each
necklace
contain?
E.2353
1
Calculate
the
PGCD
of
110
and
88
.
2
a
A
worker
has
metal
plates
110
cm
long
and
88
cm
wide.
He
was
given
the
following
instructions
:
ˇDécouper
in
these
plates
squares
all
identical,
as
large
as
possible,
so
as
to
have
no
loss.ı
What
will
be
the
length
of
the
side
of
a
square?
b
How
many
squares
will
he
get
per
plate?
E.611
1
Determine
the
PGCD
of
the
integers
108
and
135
.
2
Marc
has
108
red
marbles
and
135
black
marbles.
He
wants
to
make
packets
so
that
:
all
packets
contain
the
same
number
of
black
marbles
;
all
packs
contain
the
same
number
of
red
marbles
;
all
red
marbles
and
all
black
marbles
are
used.
a
What
maximum
number
of
packets
will
it
be
able
to
achieve?
b
How
many
red
and
black
marbles
will
there
then
be
in
each
pack?
E.614
1
a
Calculate
the
PGCD
of
494
and
43.
b
What
can
you
say
about
these
two
integers?
c
Is
the
fraction
494
43
reducible?
2
a
Calculate
the
PGCD
of
396
and
252.
A
jeweler
owns
396
rubies
and
252
diamonds.
He
wishes
to
compose
as
many
rings
as
possible
such
that
each
has
the
same
number
of
rubies
and
the
same
number
of
diamonds.
b
How
many
rings
can
he
make?
https://chingmath.fr
chapExoCorrec/603
sacados/603
DividendeDiviseurReste24832.....................×248...32...×............×............
chapExoCorrec/3550
sacados/3550
chapExoCorrec/3545
sacados/3545
chapExoCorrec/2353
sacados/2353
chapExoCorrec/611
sacados/611
Groupe Ouest - 2001 - ? points
chapExoCorrec/614
sacados/614
E.3459
A
salesman
has
a
stock
of
276
postcards
and
230
key
rings.
He
wants
to
make
ˇ
Souvenirs
de
Tahiti
and
his
Îles
ı
boxes
so
that
:
the
number
of
postcards
in
each
box
is
the
same
;
the
number
of
key
rings
be
the
same
in
each
box;
all
postcards
and
key
rings
be
used.
1
How
many
boxes,
each
containing
10
key
rings,
will
he
be
able
to
make?
How
many
postcards
will
each
box
then
contain?
2
a
Calculate
the
PGCD
of
276
and
230
,
detailing
the
method
used.
b
What
is
the
maximum
number
of
boxes
the
seller
can
make?
How
many
key
rings
and
postcards
will
each
box
con-tain?
E.619
1
Show
that
the
PGCD
of
the
integers
372
and
775
is
equal
to
31
;
write
the
calculations.
2
A
conductor
has
372
male
and
775
female
choristers
rehearsing
for
a
concert.
He
wants
to
make
rehearsal
groups
so
that
:
The
number
of
female
choristers
in
each
group
is
the
same
;
The
number
of
male
choristers
is
the
same
in
each
group
;
each
chorister
belongs
to
one
group.
a
What
maximum
number
of
groups
will
it
be
able
to
make?
b
How
many
male
and
female
choristers
will
there
then
be
in
each
group?
E.3455
1
Determine
the
PGCD
of
the
integers
75
and
45
.
2
Two
florists
have
the
same
stock:
45
irises
and
75
roses.
They
each
have
their
own
ideas
about
how
to
use
these
flowers
:
The
florist
A
wants
to
make
iris
bouquets
and
rose
bouquets
each
with
the
same
number
of
flowers.
He
also
wants
these
bouquets
to
have
as
many
flowers
as
possible.
The
florist
B
wishes
to
make
the
maximum
number
of
bouquets
all
identical
where
each
bouquet
contains
irises
and
roses.
a
Determine
the
number
of
iris
bouquets
and
the
number
of
rose
bouquets
made
by
the
florist
A
.
b
Determine
the
number
of
bouquets
of
flowers
(and
their
composition)
made
by
the
florist
B
.
E.609
For
the
village
fête,
the
patissier
prepared
bags
of
cakes.
In
some,
he
put
pains
au
chocolat
and
in
others
croissants.
He
put
the
same
number
of
cakes
in
each
bag.
there
are
a
total
of
910
pains
au
chocolat
and
693
croissants.
1
Wanting
to
put
as
many
cakes
as
possible
in
each
package,
how
many
cakes
did
he
put
in
each
bag?
2
How
many
bags
containing
croissants
are
there?
E.3379
1
Determine
the
GCD
of
120
and
144
using
the
method
of
your
choice.
Show
your
intermediate
calculations.
2
A
salesperson
has
a
stock
of
120
bottles
of
tiare
perfume
and
144
bars
of
monoi
soap.
He
wants
to
sell
all
of
this
stock
by
making
as
many
ˇSouvenirs
of
Polynesiaı
gift
sets
as
possible,
such
that
:
the
number
of
bottles
of
tiare
perfume
is
the
same
in
each
gift
set
;
the
number
of
monoï
soap
bars
is
the
same
in
each
gift
set
;
all
bottles
and
soap
bars
are
used.
Find
the
number
of
gift
sets
to
prepare
and
the
contents
of
each
one.
The
evaluation
of
this
question
will
take
into
account
ob-servations
and
research
steps,
even
if
incomplete
;
include
them
in
your
answer.
3
The
algorithm
of
successive
subtractions
can
be
used
to
find
the
GCD
of
two
given
integers.
He
uses
the
following
property:
ˇ
a
and
b
being
two
positive
integers
such
that
a
is
greater
than
b
,
PGCD
(
a
;
b
)
=
PGCD
(
b
;
a
−
b
)
ı’
On
a
spreadsheet,
Heiarri
created
this
worksheet
to
find
the
PGCD
of
2
277
and
1
449
.
A
B
C
1
a
b
a
−
b
2
2277
1449
828
3
1449
828
621
4
828
621
207
5
621
207
414
6
414
207
207
7
207
207
0
a
Using
his
spreadsheet,
say
what
is
the
PGCD
of
2.277
and
1.449
.
b
What
formula
did
he
write
in
cell
C2
to
obtain
the
result
indicated
in
this
cell
by
the
spreadsheet?
E.644
The
two
questions
in
this
exercise
are
independent.
6510
black
ants
and
4650
red
ants
decide
to
join
forces
to
fight
termites.
1
To
do
this,
the
queen
ant
wants
to
form
teams,
using
all
the
ants,
which
will
all
be
made
up
in
the
same
way:
one
number
of
red
ants
and
another
number
of
black
ants.
What
is
the
maximum
number
of
teams
the
queen
can
form
in
this
way?
2
If
all
the
ants,
red
and
black,
stand
in
single
file,
they
form
a
column
42.78
m
long.
Knowing
that
a
red
ant
is
2
mm
longer
than
a
black
ant,
determine
the
size
of
a
red
ant
and
a
black
ant.
E.608
For
May
1
er
,
Julie
has
182
sprigs
of
lily
of
the
valley
and
78
roses.
She
wants
to
make
as
many
identical
bouquets
as
possible
using
all
her
flowers.
How
many
identical
bouquets
can
she
make?
What
will
be
the
composition
of
each
bouquet?
https://chingmath.fr
chapExoCorrec/3459
sacados/3459
chapExoCorrec/619
sacados/619
Asie - Juin 2003 - 4 points
chapExoCorrec/3455
sacados/3455
chapExoCorrec/609
sacados/609
Groupe Nord - Septembre 2002 - 2 points
chapExoCorrec/3379
sacados/3379
chapExoCorrec/644
sacados/644
chapExoCorrec/608
sacados/608
Groupe Nord - Juin 2002 - 3 points
951=÷÷951GCF=1
7215=÷÷7215GCF=2
5612=÷÷5612GCF=3
1580=÷÷1580GCF=4
5.
PPCM
E.279
In
a
newly
built
house,
we
want
to
tile
the
floors
in
certain
rooms.
1
The
kitchen
floor
is
a
rectangle
of
length
4.55
m
and
width
3.85
m
.
We
want
to
tile
this
room
with
square
tiles,
without
mak-ing
any
cuts
;
furthermore,
the
dimensions
of
these
pavers
must
be
a
whole
number
of
centimeters.
a
Give
the
largest
size
of
square
pavers
that
can
be
used
in
these
rooms.
b
Give
all
possible
sizes.
2
Rectangular
tiles
of
24
cm
length
and
15
cm
width
are
available.
What
is
the
dimension
of
the
smallest
square
room
that
can
be
paved
without
any
additional
cutting
of
the
slabs?
E.1471
For
his
birthday,
Paul
has
made
a
pizza
measuring
60
cm
long
by
24
cm
wide.
He
wishes
to
cut
his
pizza
as
follows
:
Each
part
must
be
square
and
of
the
same
size.
The
dimensions
of
a
share
must
be
expressed
using
a
whole
number
of
centimeters.
Let’s
help
him
choose
the
size
of
each
slice.
1
Find
the
eight
divisors
of
the
integer
24.
2
Find
the
twelve
divisors
of
the
integer
60.
3
What
are
the
common
divisors
of
the
integers
24
and
60?
4
Give
the
possible
dimensions
of
each
slice
of
Paul’s
pizza.
6.
Us-math:
GCF
E.9637
With
American
notations:
the
ˇ
greatest
common
fac-tor
ı
(GCF)
of
two
integers
is
the
greatest
common
factor.
For
example:
the
factors
of
18
are:
1
,
2
,
3
,
6
,
9
and
18
factors
of
24
are:
1
,
2
,
3
,
4
,
6
8
,
12
and
24
Ainsi,
le
GCF
de
18
et
24
est
6
.
For
each
question,
complete
the
blanks
:
https://chingmath.fr
chapExoCorrec/279
sacados/279
chapExoCorrec/1471
sacados/1471
chapExoCorrec/9637
sacados/9637
951=÷÷951GCF=1
7215=÷÷7215GCF=2
5612=÷÷5612GCF=3
1580=÷÷1580GCF=4