Number Patterns
Primary 4 · Mathematics
Number Patterns
Lesson 1 of 4
15 min
Let's begin
Five sectors of Gicumbi district planted trees during umuganda this year. The sector leader writes the numbers on the board: 12 450, 9 875, 12 405, 21 030 and 10 999.
"Which sector planted the most trees? Which planted the fewest?" she asks.
Today you will put big numbers in order, from smallest to largest and from largest to smallest.
First count the digits. A 5-digit number is always bigger than a 4-digit number. So 9 875 is the smallest number on the board, even though it starts with a 9.
Compare the digits place by place, starting from the biggest place. Stop when two digits are different.
| Number | Ten thousands | Thousands | Hundreds | Tens | Ones |
|---|---|---|---|---|---|
| 12 450 | 1 | 2 | 4 | 5 | 0 |
| 12 405 | 1 | 2 | 4 | 0 | 5 |
Worked example 1
Which is bigger, 12 450 or 12 405?
Step 1 Ten thousands: 1 and 1. The same.
Step 2 Thousands: 2 and 2. The same. Hundreds: 4 and 4. The same.
Step 3 Tens: 5 and 0. Different! 5 tens is more than 0 tens, so 12 450 > 12 405.
Increasing order (also called ascending order) goes from the smallest to the largest:
9 875, 10 999, 12 405, 12 450, 21 030
Decreasing order (also called descending order) goes from the largest to the smallest:
21 030, 12 450, 12 405, 10 999, 9 875
So the sector with 21 030 trees planted the most, and the one with 9 875 planted the fewest.
Remember the signs: < means "is less than" and > means "is greater than". The open mouth always faces the bigger number: 9 875 < 10 999.
Look at 5, 10, 15, 20, 25. These numbers are in increasing order, and they also follow a rule: add 5 each time. A list of numbers that follows a rule is a number pattern, or sequence. Each number in it is called a term. You will study patterns in the next lessons.
Tip
Count the digits, then start at the left. More digits means a bigger number. Same number of digits? Compare from the biggest place until two digits are different.
Work each one in your exercise book first. Then tap Show answer to check.
Which is bigger: 45 609 or 45 690?
Answer: 45 690. The tens are different: 9 tens is more than 0 tens.
Put in increasing order: 8 040, 8 400, 8 004.
Answer: 8 004, 8 040, 8 400. Compare the hundreds, then the tens.
Put in decreasing order: 30 100, 31 000, 3 100.
Answer: 31 000, 30 100, 3 100. 3 100 has only 4 digits, so it is the smallest.
Write < or >: 67 999 ___ 70 000
Answer: 67 999 < 70 000. The ten thousands are 6 and 7.
Use each of the digits 4, 0, 7, 2 and 9 once. Make the smallest 5-digit number you can.
Answer: 20 479. A number cannot start with 0, so start with the smallest other digit, 2. Then put 0, 4, 7, 9.
What you learned today
Sources and credits
Written by Ganzaa. The stories, drawings and practice questions are original.
Quick check
Which number is the biggest?
