# 5.03 Notes and coins

Lesson

## Ideas

The strategy of  counting on  will be helpful in this lesson. Let's try a practice problem to review.

### Examples

#### Example 1

Write the next number in the pattern:

1,\,3,\,5,\,7,\,9,\, 11,\,⬚

Worked Solution
Create a strategy

Get the next value by counting on to complete the pattern.

Apply the idea

Count on from 1 to 3 to get the increase of 2 as shown in the number line.

So to get the next number in the pattern, we need to count on from 11 by 2. We can add them together using a place value table.

The next number in the pattern is 13:1,\,3,\,5,\,7,\,9,\, 11,\,13

Idea summary

Counting on is helpful to find the next number in a pattern.

## Coins

Countries around the world have different types of money (which are also called currencies), usually in the form of notes and coins. In Australia, we use dollars and cents as our currency.

Let's watch a video about the different Australian notes and coins and how we can use them in everyday life.

### Examples

#### Example 2

What is the value of each coin?

a
Worked Solution
Create a strategy

The value of the coin is on the coin. If the coin is silver it is in cents. If the coin is gold it is in dollars.

Apply the idea

Since the coin is silver and there is a 10 on it, the value is 10 cents.

b
Worked Solution
Create a strategy

The value of the coin is on the coin. If the coin is silver it is in cents. If the coin is gold it is in dollars.

Apply the idea

Since the coin is gold and there is a 2 on it, the value is 2 dollars.

Idea summary

The value of a coin is written on the coin.

Silver coins are for cents, and gold coins are for dollars.

We can add notes and coins together to make a new total. Watch this video to see how.

### Examples

#### Example 3

Which of the following shows a total of \$22.50? A B Worked Solution Create a strategy Add the value of each note and coin. Use this table of values to help you. Apply the idea All notes and gold coins are for dollars, and the silver coins are for cents. To add the values we can write \$5 as 5.00 and 50 cents as 0.50.

For Option A, write the addition of values in a vertical algorithm and add the digits in each column.

\begin{array}{c} & &2&0&.&0&0 \\ & &&2&.&0&0 \\ &+&&0&.&5&0 \\ \hline & &2&2 &. &5&0 \\ \hline \end{array}

The total amount of notes and coins in Option A is \$22.50. For Option B, write the addition of values in a vertical algorithm. and add the digits in each column. \begin{array}{c} & &2&0&.&0&0 \\ & &&5&.&0&0 \\ &&&1&.&0&0 \\ &+&&1&.&0&0 \\ \hline & &2&7 &. &0&0 \\ \hline \end{array} The total amount of notes and coins in Option B is \$27.00.

So the answer is Option A, which equals \\$22.50.

Idea summary

100 cents makes 1 dollar.

All notes have dollar values. The value is written on the note.

To add money we can write the values as decimals and add them using a vertical algorithm.

### Outcomes

#### MA2-5NA

uses mental and written strategies for addition and subtraction involving two-, three-, four and five-digit numbers