# How to remember rounding

To remember how to round learn this following poem

Underline the digit
Look next door
Five or more raise the score
Four or less just ignore

NOTE:

Change all the numbers to the right of the underlined number to zero.

Example 1

Round the number 1338 to the nearest hundred.

1328                   Round to the nearest hundred

1328                   Underline the digit (the hundreds column)

1328                   Look next door

2                         It’s not five or more. It’s four or less so INGORE.

1300                  Keep underlined number the same. Change all the numbers to the right to a zero.

Answer: 1328 to the nearest hundred is 1300.

Example 2

Round pi to four decimal places

3.141592653589……….

3.141592653589……….                   Round to four decimal places

3.141592653589……….                   Underline the digit (of 4th decimal place)

3.141592653589……….                   Look next door

9                                                        It’s five or more, so you must round up.

3.1416                                              5 becomes 6 and all the numbers to the right become zero.

Answer: pi rounded to four decimal places is 3.1416

Example 3

Round 28381 to the nearest thousand.

28381….                        Round to thousand

28381….                        Underline the digit (the thousand column)

28381….                        Look next door

3                                     It’s not five or more. It’s four or less so IGNORE.

28,000                           Keep underlined number the same. Change all the numbers to the right to a zero.

Answer: 28381 rounded to the nearest thousand is 28,000

Example 4

Round 28381 to the nearest hundred.

28381….                       Round to hundred

28381….                       Underline the digit (the hundred column)

28381….                       Look next door

8                                    It’s five or more. So you must round up

28,400                          3 becomes 4 and all the numbers to the right become zero.

Answer: 28381 rounded to the nearest hundred is 28,400

Example 5

Round 28381 to the nearest ten.

28381….                       Round to ten

28381….                        Underline the digit (the tens column)

28381….                        Look next door

It’s not five or more. It’s four or less so IGNORE.

28,380                          Keep underlined number the same. Change all the numbers to the right to a zero.

Answer: 28381 rounded to the nearest ten is 28,380

Example 6

Round 3.7380599 to 2 decimal places

3.7380599….                   Rounded to 2 decimal places.

3.7380599….                   Underline the digit

3.7380599….                   Look next door

It’s five or more. So you must round up

3.7400000                       3 becomes 4 and all the numbers to the right become zero.

Answer: 3.7380599 to 2 decimal places is 3.74

Example 7

Work out sqrt59 on a calculator to one decimal place.

sqrt59 on a calculator is 7.681145……

7.681145……                Round to one decimal place

7.681145……                Underline the digit

7.681145……                Look next door

It’s five or more. So you must round up.

7.7000                          6 becomes 7 and all the numbers to the right become zero.

Answer:  sqrt59 to 1 decimal place is 7.7