This lesson will show
how to perform operations
with mixed numbers using the
Desmos scientific calculator.
For the first example,
we have four and two fifths
plus one and two thirds.
The only way I was able to figure out
how to enter a mixed number
was to first enter the fraction
and then the whole number on the left.
So for four and two fifths
enter two divided by five,
left arrow, left arrow, and
then the whole number of four
and now right arrow over to the right side
of the mixed number.
And then we have plus
for one and two thirds,
enter two divided by three,
left arrow, left arrow, one,
and then enter.
On the right, we have the decimal
approximation for the sum,
but notice how the decimal does tell us
the whole number part of the sum is six.
We just need to convert the
decimal part to a fraction
to determine the fraction
part of the mixed number.
So now we will click answer,
which brings up the previous answer
and then subtract the six,
which just leaves the decimal,
which will now convert to a fraction
by clicking the circle on the far right,
which will convert the
decimal to a fraction.
Now we know the sum is six and one 15th.
Going back to the calculator,
just for a moment,
we could have clicked the
convert to fraction button here,
which will give us the
improper fraction of the sum,
but normally when working
with mixed numbers,
they do want the answer
back as a mixed number.
Next, we have seven and four fifths
minus two, and two thirds.
For seven and four fifths
enter four divided by five,
left arrow, left arrow, seven,
right arrow to the right,
and then minus for two and two thirds,
enter two divided by three, left arrow,
left arrow, two, enter.
Again on the right,
we have the decimal
approximation for the difference.
The five indicates the whole number part
of the mixed number is five,
so now we'll click answer, subtract five,
which leaves us with just the decimal part
and now we'll convert the
decimal part to a fraction
to determine the fraction
part of the mixed number.
And now we know the difference
is five and two 15ths.
And now let's find a
product and a quotient.
For the product, we have two and two 15ths
times four and three eighths.
For two and two 15ths,
we entered two divided by
15, left arrow, left arrow,
left arrow, two, right
arrow to the right times.
For four and three eighths,
we enter three divided
by eight, left arrow,
left arrow, four and enter.
Looking at the decimal
approximation for the product.
We know the whole number part
of the mixed number is nine.
To find the fraction part,
we need to convert the
decimal part to a fraction.
So we'll click answer minus nine, enter,
and then convert the
decimal to a fraction,
which gives us one third,
which you may have recognized.
The product is nine and one third.
Again, if we were able to give the answer
as an improper fraction,
we could click convert to fraction here,
which gives us 28 thirds.
But again, normally when
working with mixed numbers,
they do want the answer
back as a mixed number.
So again, we have nine and
one third as a mixed number.
And for our last example,
we have a quotient.
We have six and five sixths
divided by two and one third.
So we will enter five
divided by six, left arrow,
left arrow, six, right arrow to the right
divided by, notice how it
gave us a fraction bar,
but that's okay
because the fraction bar
does represent division
for two and one third,
we enter one divided by three left arrow,
left arrow, two, and enter.
And again, looking on the right,
we can see the whole
number part of the quotient
is two to find the fraction
part of the mixed number.
We need to convert the
decimal part to a fraction.
To do this, we click
answer minus two enter
and convert the decimal to a fraction,
which is 13 14ths.
We now know the quotient
is two and 13 14ths.
I hope you found this helpful.
