Functional Skills: Number Basics

Two-Digit and Three-Digit Numbers

Using the First Digit to find the Lowest and Highest Number

We can compare the first digits of different numbers to see which one is the lowest, or highest.

Example: Find the lowest number in the list:

$172, 42, 220, 20, 59, 367$

Step 1: Find the numbers with the least number of digits:

$textcolor{red}{4}2, textcolor{red}{2}0$ and $textcolor{red}{5}9$ all have $2$ digits

Step 2: Find the number with the smallest first digit:

$textcolor{orange}{20}$ is the smallest since $textcolor{red}{2}$ is the smallest from $textcolor{red}{4}, textcolor{red}{2}$ and $textcolor{red}{5}$

So, $20$ is the lowest number.

Example: Find the highest number in the list:

$172, 42, 220, 20, 59, 367$

Step 1: Find the numbers with the most number of digits:

$textcolor{red}{1}72, textcolor{red}{2}20$ and $textcolor{red}{3}67$ both have $3$ digits

Step 2: Find the number with the biggest first digit:

$textcolor{orange}{367}$ is the biggest since $textcolor{red}{3}$ is the biggest from $textcolor{red}{1}, textcolor{red}{2}$ and $textcolor{red}{3}$

So, $367$ is the highest number.

Using Other Digits to find the Lowest and Highest Number

If there are $2$ or more numbers that have the same number of digits, and their first digit is the same, then you will need to compare the second digits.

The number that has the lowest second digit is the lowest, and the number with the highest second digit is the highest.

If the second digits are the same then you will need to compare the third digits and so on.

Example: James is $142$ cm tall, Betty is $97$ cm tall, Susie is $148$ cm tall and Dylan is $88$ cm tall.

Who is the tallest?

Step 1: Find the numbers with the most number of digits:

$textcolor{red}{1}textcolor{blue}{4}textcolor{limegreen}{2}$ cm and $textcolor{red}{1}textcolor{blue}{4}textcolor{limegreen}{8}$ cm

Step 2: Find the number with the biggest first digit:

They are both the same – $textcolor{red}{1}$

Step 3: Find the number with the biggest second digit:

They are both the same – $textcolor{blue}{4}$

Step 4: Find the number with the biggest third digit:

$textcolor{orange}{148}$ is the biggest since $textcolor{limegreen}{8}$ is bigger than $textcolor{limegreen}{2}$

So, Susie is the tallest.

Ordering Numbers

Ordering numbers expands on what you have just learned.

Example: Jordan has $5$ balls of different weight:

$65$ g, $4$ g, $24$ g, $183$ g, $112$ g

Put the balls in order of weight from smallest to largest.

Step 1: Put the weights into separate groups, starting with the numbers with the fewest digits:

$1$ digit:                     $4$ g

$2$ digits:       $65$ g, $24$ g

$3$ digits: $183$ g, $112$ g

Step 2: Put the numbers in order from smallest to largest within each group:

$4$ g,           $24$ g, $65$ g          $112$ g, $183$ g

Step 3: Write out the final order (put the numbers from step 2 together):

$4$ g, $24$ g, $65$ g, $112$ g, $183$ g