In this video, we will look
at three examples of rounding to the nearest whole number
or ones place value.
We will round using the number line
as well as the formal rules.
We first have 7.81936.
Using the ones place value, we first need
to recognize that 7.81936 is between 7 and 8
on the number line and 7.5 would be right in the middle.
And now let's plot the given number on the number line.
7.81936 is between 7.5 and 8, closer to 8
than it is to 7.5.
Let's say it's approximately here.
When rounding to the nearest whole number
or ones place value, we need to determine
whether the given number is closer to 7
or closer to 8.
Using the number line, we can see
7.81936 is closer to 8 than it is to 7
which is why 7.81936 rounds up to 8
when rounding to the nearest whole number
or ones place value.
And now let's look at the formal rules surrounding.
The first step is to find the digit
in the rounding place value because we are rounding
to the nearest whole number,
we locate the 7 in the ones place value
which is here.
The next step is to locate the digit
to the right of the rounding place value,
which in our case is the 8.
The 8 indicates whether we round up or down.
The digit to the right of the rounding place value
is 5 or less, we round down.
To round down, the digit in the rounding place value
stays the same.
If the digit to the right of the rounding place value
is 5 or more, we round up, which is our case
because we have an 8.
To round up, the digit in the rounding place value
increases by one.
Notice 7 + 1 does give us 8.
Next we have 234.35.
Using the ones place value,
this is between 234 and 235
where in the middle we have 234.5.
And now we plot 234.35 on the number line
which is between 234 and 234.5
and 234.35 would be a little closer
to 234.5 then 234
let's say approximately here.
To round to the nearest whole number
or ones place value, we need to determine
whether 234.35 is closer to 234 or 235.
Using the number line, we can easily see
234.35 is closer to 234 than it is to 235
which is why 234.35 rounds down to 234.
We're using the formal rules.
We first locate the 4 in the ones place value
and then we locate the digit to the right
which, in this case, is a 3.
Because the 3 is less than 5, we round down.
To round down, the digit in the rounding place value
stays the same which does give us 234.
And for our last example,
we want to round 89.5 to the nearest whole number
or ones place value.
Using the ones place value,
89.5 is between 89 and 90 and 89.5 is right in the middle.
Notice in this case, the given number
is right in the middle.
It's the same distance from 89 as it is from 90.
Whenever the number is right in the middle,
we always round up which means 89.5
rounds up to 90 when rounding to the nearest whole number
or the ones place value.
Using the formal rules, we first locate the 9
in the ones place value.
Notice now we have a 5 to the right
because 5 is 5 or more, we round up.
To round up, the digit in the rounding place value
increases by one.
Because we have a 9, 9 + 1 is 10,
we perform an exchange.
80 + 10 is 90.
If we want, we can just think 89 + 1 is 90.
I hope you found this helpful.