Chapter 1.5 (Mathematics 5)

Rounding off numbers up to tens of thousands

Rounding off numbers to the nearest hundreds

In groups of three:

  1. Draw a number line, mark and label equal intervals from 70 400 to 70 500 as shown.
  1. List numbers on the number line smaller than 70 450.
  • 70 400
  • 70 410
  • 70 420
  • 70 430
  • 70 440
  • 70 460
  • 70 470
  • 70 480
  • 70 490
  • 70 500
  1. Check whether the numbers are nearer to 70 400 or to 70 500.
  • 70 400
  • 70 500
  1. List the numbers on the number line greater than 70 450.
  • 70 400
  • 70 410
  • 70 420
  • 70 430
  • 70 440
  • 70 460
  • 70 470
  • 70 480
  • 70 490
  • 70 500
  1. Check whether the numbers are nearer to 70 400 or 70 500.
  • 70 400
  • 70 500
  1. Discuss and share with other groups.

Note

To round off a number to the nearest hundred.

Check on the digit in the tens place value.

If the digit is greater than 5 or equal to 5, then the digit in the hundreds place value increases by 1. Put zero in the tens and ones place value.

If the digit is less than 5, the digit in the hundreds place value remains the same. Put zero in the tens and ones place values.

Example 8

Round off each of the following numbers to the nearest hundred.
  1. 8 672
  1. 38 426
  1. 72 193
  1. The digit in the tens place value is 7 which is greater than 5.
    ​So 8 672 is 8 7 00.
  2. The digit in the tens place value is 2.
    ​So 38 426 is 38 400.
  3. The digit in the tens place value is 9.
    ​So 72 193 is 72 200.

Exercise J

8 732 is 

2 546 is 

76 086 is 

99 328 is 

5 099 is 

J2

Bahati had Sh 25 789 in his bank account. How much money to the nearest hundreds did Bahati have in his account?

J3

The length of a section of a railway line is 41 860. Write the length of the railway line to the nearest hundreds.

J4

A fish farmer sold 19 308 kg of fish in a given month. Round off the amount of fish to the nearest hundreds.

J5

A tanker carried 22 104 litres of diesel. How much diesel to the nearest hundreds did the tanker carry?

J6

The population of cattle in a sub-county was 92 568. Write the number of cattle to the nearest hundreds.

Rounding off numbers to the nearest thousands

In groups of three:

  1. Draw a number line to represent numbers between 2 000 and 3 000.
  1. List numbers on the number line that are nearer to 2 000 than 3 000.
  • 2 100
  • 2 200
  • 2 300
  • 2 400
  • 2 500
  • 2 600
  • 2 700
  • 2 800
  • 2 900
  1. List the numbers on the number line that are nearer to 3 000 than to 2 000.
  • 2 100
  • 2 200
  • 2 300
  • 2 400
  • 2 500
  • 2 600
  • 2 700
  • 2 800
  • 2 900
  1. Discuss and share the results with other groups.

Note

To round off a number to the nearest thousands.
  1. Check on the digit in the hundreds place value.
  2. If the digit is greater than 5 or equal to 5, the digit in the thousands place value increases by 1. Write zero in the hundreds, tens and ones place values.
  3. If the digit is less than 5, the digit in the thousands place value remains the same. Write zero in the hundreds, tens and ones place values.

Example 9

Round off 84 869 to the nearest thousands.

The digit in the hundreds place value is 8 which is greater than 5.

So 84 869 is 85 000 to the nearest thousands.

Exercise K

6 575 is 

27 023 is 

51 649 is 

89 728 is 

K2

An athlete covered 41 953 metres in a marathon race. Round off to the nearest thousands the distance covered by the athlete.

K3

A milling factory produced 29 156 kg of millet flour on a certain day. Round off to the nearest thousands the amount of flour produced.

K4

The amount of water in a tank is 14 965 litres. How much water is in the tank to the nearest thousand? Round off to the nearest thousands the amount of water in the tank.

  • 80 000
  • 84 000
  • 84 600
  • 85 000