Round a Number

Find the number in the hundredth.
It's 1.

2: ones
0.7: tenth
0.01: hundredth
0.008: thousandth
0.0002: ten-thousandth
0.00008: hundred-thousandth

See the number on the right side of the 1.
It's 8.
This 8 [is greater than or equal to 5].
Then [add 1] to the hundredth number 1:
1 + 1 = 2.

So write 2.72.
Drop the numbers
on the right side of the hundredth:
828... .

So 2.72 is the answer.

Find the number in the hundredth.
It's 4.

See the number on the right side of the 4.
It's 1.
This 1 [is not greater than or equal to 5].
Then [leave] the hundredth number 4.

So write 3.14.
Drop the numbers
on the right side of the hundredth:
1592... .

So 3.14 is the answer.

Find the number in the tenth.
It's 1.

See the number on the right side of the 1.
It's 4.
This 4 [is not greater than or equal to 5].
Then [leave] the tenth number 1.

So write 3.1.
Drop the numbers
on the right side of the tenth:
41592... .

So 3.1 is the answer.

Find the number in the thousandth.
It's 1.

See the number on the right side of the 1.
It's 5.
This 5 [is greater than or equal to 5].
Then [add 1] to the thousandth number 1:
1 + 1 = 2.

So write 3.142.
Drop the numbers
on the right side of the thousandth:
592... .

So 3.142 is the answer.