Fraction and Decimal 003 Video Lecture - Class 7

on last one we have stirred division of
fractions today we will do some cushions
based on it if the cost of 52 x 5 liters
of milk
is rupees 101 1 by 4 then we have to
find its cost price per liter here we
have given the cost price of 52 by five
liters of milk and we have to find the
cost of one liter of milk so whenever we
are given the quantity quantity of a
cost of more and we have to find for
less we will always divide so here you
can write costs off 52 by five liters of
milk is rupees 101 wonderful or we can
write cost of 27 by five we have
converted this mixed fraction into the
improper fraction the thirst of milk is
rupees now we can convert this improper
fraction of extraction also into the
improper fraction that will be equals to
405 upon 4 so the cost of one litre of
milk will be rupees 405 by 4 / 27 by
five now when we convert the division
sign into multiplication sign we will do
the reciprocal of the number which is
written on the right side of the
division sign so it will be five by 27
on simplification we will get T equals
two rupees that will be close to rupees
75 by four and if we convert this into
mixed fraction it will be posed two
rupees 18 3 by 4 so the cost of one
litre of milk will be rupees 18 3 by 4
one more question art in contains 18 kg
of King after consuming
2 by 3 of 8
how much G is left
in the 10 now here we are given the
quantity of gear is it enough in the tin
and we have consumed three x we have
consumed 2 x 3 part of it and we have to
find how much key is left in the temp so
we can do this question in two ways
first method is we know that to buy
third of the part of the ghee has been
consumed so we will find out the
quantity of the ghee which has been
consumed so the quantity
of gay consume will be equals to 2 by 3
of 18 kg that will be equal to 2 by 3
into 18 of means multiplication so it
will be equals to 12 kg now this part
has been consumed so the left part
of key will be equals to 18-12 that is
equals to 6 kg the second way of doing
this question is we know that too bad
third part of the ghee has been consumed
so the left part will be 1 minus 2 by 3
that is we have subtracted 2 by 3rd part
from the whole part that is from one
which will be equals to 1 by 3 now this
is the left part so we can write the
left part of ki will be 1 by 3 of 18 kg
which will be again equals to 6 kg next
we come to decimals
the simmers are the extensions of our
number system these are fractions with
denominator ten hundred thousand etc for
example if a number is written as 3 upon
10 we can write it as 0.3 so this is the
decimal representation of 3 by 10 which
is a fraction here 3 the number which is
written after the decimal is known as
the decimal number of decimal places
here we have only one number after the
decimal therefore we have only one
decimal place
if the number would be to 3.2 48 here
you can see that we have three numbers
written after decimal so we have three
decimal numbers or we can say three
decimal place
next is like and unlike decimals
if two decimals have decimal numbers
have same number of decimal places for
example if I am having a number zero
point five six three and another number
three point two eight nine here you can
see I am having three digits or three
different numbers after decimal here
also I am having three numbers after
decimal so these two numbers are like
decimals
but if I am having a number six point
seven three two and another number five
point eight 693 here we have four
decimal places and here we have three
decimal places so these two numbers are
unlike decimals
as they are having different
number of decimal place
we can convert unlike decimal
to a like the soon
for example if I am having a number
three five point six nine eight that is
35.6 98 and another number 2.05 not to
convert these two into life decimals so
I can just put 10 after five so it will
also have three decimal places and here
also we are having three decimal places
so these two numbers are like decimal we
can take one more example if I am having
a number 0.5 and another number 5.25 now
to convert these two numbers intellect
isomers I can just put a zero after five
so both of these numbers will have the
same number of decimal places next is
comparison of dicing
for comparing the decimals first of all
we will compare the whole number part of
the decimal for example we are having
two decimal numbers 36.2 nine and
another number thirty-seven point two
nine here you can see that the whole
number part is 36 and in this number the
whole number part is 37 just by seeing
the whole number part we can say that
thirty-seven point two nine is greater
than thirty six point two nine let us
see another example
20 9.6 38 and another number is 62 5.28
here so you can see that 625 that is the
whole number part of the second number
is greater than the whole number part of
the first number so we can simply say
that 620 5.28 is greater than 200 9.6 38
but if the whole number parts are same
for example if we have a number 3939
point 28 and another number 39.50 here
you can see the whole number part is 39
and in the second number it is also 39
so first of all we will compare the
leftmost digit present in the decimal
that is to here and here it is 5 so 5 is
greater than 2 so 39.50 is greater than
30 9.28 let us see one more example we
have to compare 65.2 389 and 65.2 387
now if we start comparing first of all
we see the whole number part which are
same so we have to compare the decimal
part here the first number is to hear
the first number is also to next digit
is 3 here and next now digit here is 3
again we have the same numbers now we
come to the third number here it is
eight and here it is also a now we'll
come to the last digit that is nine here
and here it is seven and seven is less
than nine so we can say that 65.2 387 is
less than sixty five point two two
89 next is conversion of
decimals
into fraction
if we are given a number six point two
nine and we have to convert this decimal
number into fraction it is very simple
first of all we will write the numbers
six to nine and we are having two digits
or we can say two decimal places so we
will put two zeros after one in the
denominator this is the fractional
representation of decimal 6.29 another
example we have to convert 0.25 into the
fraction that will be equals to 25 that
is the number whole upon we have only
two testing two decimal places so we
will put two zeros in the denominator
now here you can see that 25 and 100 are
having five common so we can cancel it
so we can cancel it by five five times
and 120 times again we can see there is
common five so we will cancel 5 by 5 1 x
+ 20 x 54 times so it will be equals to
1 by 4 so this is the fractional
representation of 0.25 I have to
represent 0.009 so i will write 9 that
is the number and how many decimal
places i am having one two and three so
i will put three zeros after one in the
denominator this is the decimal
representation of 0.009 now let us see
the converse of this if I have to
convert a fraction into decimal that is
conversion of
fraction
into decimal
it is very simple if we are having the
fractions as the decimal fractions that
is we are having if I am having a number
two by 10 so it is very simple to
convert this desk number into decimal we
are here when we are not having any
decimal point in the number that means
they're similis present and the last and
we are having 10 here so we will shift
the decimal which is present after to
one place on the left that is here we
can put the decimal so it will be equal
to 0.2 let us see one more example if I
am having a number 635 up 100 so i can
write it as 635 now where is the decimal
it is present here now since I have to
since the in the denominator i am having
hundred that is two zeros so the decimal
will shift to places the left and it
will be equal to six point three five
one more example if i have to convert
29.5 upon thousand so it will be equals
to hear i can say the decimal and i have
to ship it three decimal three places to
the left so it will be equal to first
let me write the number 2 95 the decimal
is here so it will ship 1-2 now I don't
have any number here so I will simply
put a zero and shift the decimal to this
place so it will be equals to zero point
zero 295 now if I have to convert now
have to convert next example is I have
to convert 9 1 by 4 into decimal so i
can write it as 9 plus 1 by 4 or i can
simply write it as 9 plus 1 into 25 into
14 into 25 by multiplying for by 25 it
will be converted into hundred so it
will be equal to 9 so it will be close
to nine plus 1 upon 25 upon 100 so it
will be close to nine point two five