How Long Does It Take? | math | الصف الرابع الابتدائي
hi everyone now measuring time has
occupied the minds of people since the
beginning of the ancient civilization in
egypt and the world measuring time
dashes
some nations fish have used the sun will
moon will stores ascend the side home in
telling time and measuring time till
today la reita and herda we use the same
system machine benefiting zom and the
units of measurement that we were used
in those civilizations meant five
thousand years ago the
now we'll find out all about the
information and more in today's lesson
i miss tara we will discuss today the
remaining and elapsed time in our lesson
how long does it take it's really busy
out there today
look over there what are they doing
they're going to build something i
wonder how long it will take for it to
be built we could keep a watch on the
building and make a timeline
what's a timeline a timeline shows
changes over time we add dates to the
timeline it is a way of keeping a record
building homes and shops takes a long
time this timeline may start today but
might not be complete for a while
let's get a timeline started
let's use a timeline today to do some
time calculations how long did it take
from when the digger started to when the
builders started to lay the bricks
how do you think we can work this out
we will understand the meaning of
remaining and elapsed time hanarthy and
remaining time and elapsed time and
we'll practice using them we will use
more than one strategy and instead of
the octane strategy to help us answer
questions and solve any time related
problems easily
now we'll start with access on page 134
in your book and we will try to help
dahlia to convert the time she took to
drive to her grandmother's house by car
let's see it all together
here it took dahlia as you see here it
took dahlia two hours and fifteen
minutes hashem tells a little
grandmother
and she needs to calculate what time in
minutes only either
bill minutes how many minutes
type you can use the error analysis
chart to explain your thinking show what
the students
what is the correct answer
using this table or the error analysis
table and now i'll give you time to
think and write your thoughts and then
we will get back and discuss
it's clear that while the henaya
converted the hours into minutes how a
little hours two minutes we came in she
added twelve plus fifteen correctly
ballet at the table
here's my table iba ilha la malita right
yes i will write in the first column
that she wrote
or and she converted
the
hours
into
minutes
we came in i made a and she added
correctly
and added
correctly
wrong
yes she multiplied by six metal
multiplied by 60. okay she multiplied by
six the height hamlet
she multiplied
by six
and which is wrong okay now let's write
the correct answer in the third column
as you see here
uh
what is the question question can 92
hours and 15 minutes
2 times 60 which is
120 like you see here by two times 620
plus what plus in minutes between
15 minutes so
120 minutes plus 15 minutes equals
135 minutes and this is the correct
answer
type now we need to pay attention to the
units when answering any problem like
dalia's problem and i'll tell you again
our today's objective is we need to
understand and practice using elapsed
time and use strategies to help us solve
the problems easily
that's why we will move to build on page
135.
in this activity we have a story problem
type now do you remember the difference
between the story problem terrafor to
effer in my very story problem one
number problem
like the ones we saw before in the last
lesson
story problem number problem in the
story problem we need to read the
problem carefully beneath the problem
information that we need to focus on and
other information we don't need mental
information
s
the problem here is about let's see here
is page 135 is talking about pharah
whose goal is to run every day battery
every day an hour and 30 minutes will
you take you an hour and 30 minutes to
train for a marathon if she starts
running at 8 35 look here she starts
running at 8 35
so what time did she finish running
yes it is clear here that it is not just
about converting time
best converting time as we have learned
in the last lesson the problem here is
about elapsed time yani
which means the time needed to do
something
so we can add 1 hour and 30 minutes to 8
35 now let's do it all together
one hour and
30 minutes right
okay she started at what at what she
started at 8
35.
so what should i do i will
i will add one hour to 8 35
type
this is the hours 8 plus 1 hour gives me
nine thirty-five
but
i will add the minutes hamil 30 plus 35
type 30 plus 35 gives me what yes gives
me 65.
right here i have nine sixty five
time here nine sixty five d and among
sixty five sixty five d money in the
sixty plus five
with sixty money in one hour 60 yen one
hour so i will add one hour to nine yani
ten hours
and five minutes
and this is the time for a finish the
running
so the final answer will be ten and five
minutes ten hours and five minutes
now we can of course convert and add
using more than one way
we can use the way you preferred
now we focus on these ways on the next
problems in this part of build we will
focus on two strategies these two
strategies
align to solve the problems on elapsed
time these strategies are open number
line i will hager and milham about open
number line and conversion now we'll
apply these two strategies to the next
example let's see this example
here in this example he told me that
gamal is hiking in the park gamel beam
chiffield park he has been hiking for
two hours and thirty talon kid
two hours and thirty ah dmc for two
hours and thirty minutes
then
he has fifty five minutes more to hike
before kamen might take fifty five
hashem usual 55 minutes
okay
now how long will his whole height take
either
we can use a number line like the one we
have used before cleaning the number
line
with additional subtraction and we can
use keep counting to reach a benchmark
the only difference is you'll skip
that skip is defined from the start no
early 55 minutes
so when we are trying to reach the
benchmark we will subtract the time we
need from 55 minutes we have
the italian about the number line here's
the number line then what should they do
yes i will write on the left the first
hiking time here can it e yes
two hours and thirty
missy i will higher two hours and 30. we
can first try to reach a benchmark time
i will hug a in an household will
benchmark time
like benchmark
a benchmark yes three hours the version
of three hours what should i do yes i
will add 30 minutes
right here is 2 30 plus 30 if any
questions till three hours
type when either three hours only no
then i will add
50 sorry now i want to reach 55 right
type for dele at the e
yes for the adi we'll subtract the 30
minutes from 55 minutes we already got
taiwab andy i will have 25 minutes left
i'm at 55
minus 30.
25 minutes
25
minutes right
three hours and 25 minutes
and now this is the answer this is how
long the hike will take
now we can also round 55 fee battery in
and around 55 minutes and also little
hour there'll be 55 minutes for the la
at the ocean outside hour yes i will add
five minutes right
2 30.
number line here i have 2 30.
and also 55 minutes size i was so happy
60 minutes you have mlt plus five
minutes right
okay you have a 60 minutes
with one hour dialogue with one hour
with one hour house only fin household
to 3 30 household to 3 30.
when either 3 30 well well
in five minutes yes i will take it five
minutes
i'll move here minus five minutes five
minutes
to be
3
25
minutes
this is another way now please note we
write the time in equation using the
colon
two points
and separate between hours will minutes
with y
type now let's use a completely
different strategy from
here is another strategy i will use it
we will use the conversion strategy talo
bunch of ale conversion strategy we can
start first by adding the minutes oh
well
adding the minutes
230
were
55 right
30 minutes or 55 minutes i dig it then
and then i can add the minutes top 30
plus 55 equals what equals
85
and the year eighty-five minutes the
mission 85
60
and 25
with 60d is one hour
60 is one hour if
he has a with her little hours if a 2
plus 1 gives me 3 1 how many minutes
25 minutes and this is my answer
okay
now
as you see here i add the hours hotel
minutes for lolly layer 25 minutes
okay now
the answer is
three hours and 25 minutes
type hegetania we can convert all the
units to minutes at the start
as follows
here i have two two
to the end then we will add them all
together
the answer will be 205 minutes
answer is 25 minutes
then i will convert them again two hours
haha will buy 205 minutes dual hours how
i i will tell you how many 205 100
either either for 205 d via cam hours i
will head i will subtract 60 from 205
205 minus 60 equals what yes 145
type again i will subtract 60 from 145
gives me what gives me 85
mum containing subtract again 60 from 85
gives me what yes of course gives me
25 minutes
so how many hours do i have here
michelangelo subtracts 60 three times oh
this is the first time second time third
time if i had to come hours minute 205
yes three hours
one day how many minutes yes i have 25
minutes
but this is the time he will take
in this problem
here in the second part in build on page
135 we have four problems on elapsed
time let's see it all together
here's page 135
type here in problem 2
to apply what you have learned i will
apply what we have learned now you can
use whatever strategy you prefer
questions
whether it is the number line strategy
eminent number line strategy or the
conversion strategy or even standard
edition as you like
then when we are back we can compare
your answers to mine
now here in problem 2
we want to add 3 hours and 25 minutes to
45 minutes type the sum of the minutes
is hamil i will heger hamill additional
minutes
25 plus 45 okay 25
plus
45 gives me what gives me 70 minutes
okay and i'll delete any 70 minutes
that'll be 70 minutes
around 60 plus one one elite diamond bam
is 60 action 60 money
one hour one more hour type 60 means one
hour if hazelwood one hour a la three
hours to be four hours four hours and
what four hours and
sorry 70 of around 60 plus 10 and one
hour with 10 minutes i add one hour to
three but four hours and
10 minutes
now you'll find in problem four let's
see problem four
here is problem number four
janna and maha has five hours to watch
three movies okay and five hours hashing
it for regular three movies that last i
will movie but
one hour and 22 minutes
in second movie two hours and 12 minutes
tell it movie with one hour and 57
minutes
do the girls have enough time to watch
all these three movies
yes first of all
three movies right
in five hours duel
one hour 22
plus
two hours
and twelve
plus one hour and fifty seven
type when i add all this the answer is
five hours and thirty one tab
is
three movies no of course the sum is
more than five hours made them some
actors in five hours if they can't
complete all the three movies type let's
move to the next
part here janna omaha
they watch the two shortest movies
so
what should they do yes they want to
know when they will finish the two
movies if they start watching at 5 30.
type now they have to exclude the
longest movie and is the longest
movie edition the two shortest movie
so i will add the two shortest movie
one hour 22 minutes and one hour 57
minutes duly to shortest
three hours nineteen let's start in time
with
5 30.
319 gives me 8 hours and
49 minutes and that will be the time the
movies end
okay now in connect on page 136 137 in
your school book you will find
interesting information in time the
units of measurement and reasons for for
using the current units of time
with which we started our lesson
now you'll be enjoying the reading and
it will expand your knowledge
now you have a chance to apply what you
have understood in practice on page 136
in this page
now problems number one to four let's
see
here is problem from one to four these
problems are very direct so you like the
ones we have solved together
and you can answer them by your own now
let's answer problem number five and six
all together and see what they are about
now in problem number five this is
problem number five problem number five
is talking about ant's life it says an
ant's first nap a will nap will end and
the day began at
the next
7 45 a.m
and lasted for 60 seconds of third
highway 60 orbital 60 seconds
what time did the ant wake up
at 7 45 am up what 60 seconds type when
she wake up
hamilti
yes diabetes 60 seconds equal 1 minute
which is 60 seconds
equals
1 minute
i will add one minute to 45
7
45
plus
1 minute
gives me what yes gives me 7
46 and this is the time the ant wake up
okay
type and now let's move to problem
number six problem number six here's
problem number six
28 problem number six only the ant then
worked and thought to start in the
colony for three hours and 13 minutes
before its next snap
the question is
what time did the aunt take his second
nap
second
homily yes i will add 3 hours 13 minutes
ham 3 hours
13 minutes
add to the sum of the last problem okay
7 46 plus 3 13.
746 plus 313 equals 10
and sorry
give a second
at 10
59 and this is the time for the second
nap the title end
now we have done our lesson talon
okay
today we have explored and practiced
solving elapsed time and problems and
learned different strategies for solving
like the number line will conversion i
want you to go back to the learning
objectives of the lesson read them again
and add the store to the next
to next to the objective that you have
understood
objectives
on it you can also check your
understanding of what we have learned
today by practicing solving problems in
your books
you can scan the code found on page 134
and this will direct you to the digital
version of the book
now we'll meet again in next lesson
thank you so much and see you soon
English (auto-generated)