Junior Number

What is Junior Number about?

The Junior Number topic is all about giving young people a set of maths and logic skills so they can solve real world problems.

By the end of the Number topic, students should know how to:

add and subtract fractions with different denominators by using equivalent fractions
multiply and divide two integers, two fractions, or two decimals
find fractions, decimals, or percentages of a number
compare fractions that arise from division-as-sharing (e.g., sharing 2 among 5 vs sharing 3 among 7)
simplify fractions using the highest common factor
use rates to model and represent change
use and apply ratios to model everyday situations

The following page covers each of these skills.

Add / Subtract Fractions

Students should know how to add and subtract fractions with different denominators by using equivalent fractions.

To learn to do this, watch this video here.

Multiply / Divide Integers and Decimals

Students should know how to multiply and divide two integers or two decimals.

To learn to do this, watch this video here.

Multiply / Divide Fractions

Students should know how to multiply and divide two fractions.

To learn to do this, watch this video here.

Fractions, Decimals, and Percentage Conversion

Students should know how to find Decimals, Fractions, and Percentages of numbers.

To learn to do this, watch this video here and use the examples below to see how to find Decimals, Fractions, or Percentages of numbers.

Decimal of Number

Let's say I want to find 0.5 of $20

of means times or ×

So 0.5 of $20 is the same as 0.5 × $20

0.5 × 20 = 10

so 0.5 of $20 is $10

Fraction of Number

If I wanted to find 5/10 of 20

the / just means divided by or ÷

So 5/10 is the same as 5÷10

5÷10 = 0.5

So 5/10 of $20 is the same as 0.5 of $20

5÷10 = 0.5

0.5 × 20 = 10

So 5/10 of $20 is $10

Percentage of Number

If I wanted to find 50% of $20

the % means divided by 100 or ÷ 100

So 50% is the same as 50÷100

50÷100 = 0.5

So 50% of $20 is the same as 0.5 of $20

50÷100 = 0.5

0.5 × 20 = 10

So 50% of $20 is $10

Comparing Fractions

Students should know how to compare fractions that arise from division-as-sharing (e.g., sharing 2 among 5 vs sharing 3 among 7).

To learn to do this, watch this video here.

Simplify Fractions using the HCF (Highest Common Factor)

Students should know how to simplify fractions using the highest common factor.

To learn to do this, watch this video here.

Rates

Students should know how to use rates to model and represent change.

To learn to do this, watch this video here.

Ratios

Students should know how to use and apply ratios to model everyday situations.

To learn to do this, watch this video here.

Other Number Skills

The following are other number skills that are good to know.

Students should also know how:

to round a number to a set number of decimal places (d.p.) or significant figures (s.f.)
to add or take away Goods and Services Tax (GST)
interest works and therefore why saving is good.
New Zealand's progressive tax system works.
to convert foreign currency to NZ currency and visa versa.

Rounding

Students should know how to round a number to a set number of decimal places (d.p.) or significant figures (s.f.).

To learn to do this, watch this video here.

Goods and Services Tax (GST)

Students should know how to add or take away Goods and Services Tax (GST)

To learn to do this, watch this video here.

Interest Payments

Students should know how interest works and therefore why saving is good.

To learn to do this, watch this video here.

Progressive Tax

Students should know how New Zealand's progressive tax system works.

To learn to do this, watch this video here.

Foreign Money Exchange

Students should know how to convert foreign currency to NZ currency and visa versa.

To learn to do this, watch this video here.

Let's say I want to convert £100 British Pounds into New Zealand Dollars ($).

The current exchange rate is £1 British Pounds to $1.94 NZ Dollars.

First draw a table with a British and NZ Column and 3 rows; the currency, the Exchange rate, and the dollar amount.

Then to each box, add in the information you know.

You know for the Exchange Rate Row, the NZ Value is 1.94 and the English Value is 1.

For the Dollar ammount, we are looking to find the NZ Value and we know the English value is £100 British Pounds.

Lastly, we Divide Up, Multiply Across.

Take the dollar amount, divide that by the number above it, then divide it by the number across. In this case:

100 ÷ 1 = 100
100 × 1.94 = 194
£100 British Pounds = $194 NZD

Check Your Understanding

You can check your understanding of the topic with the task below.

Answers are on the last slide.

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