‘Standards units in number’ is designed to transform the teaching, training and learning of mathematics in secondary schools. It is made up of teaching and learning resources – based on number – which include lesson plans, activities and links to useful computer programs. The units focus on selected topics. The plans and activities were developed with teachers and trainers and are based on successful practice.

## Unit N1: Ordering fractions and decimals

These activities for secondary mathematics lessons help pupils to interpret decimals and fractions, using scales and areas, find equivalent fractions and relate and order fractions and decimals. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N2: Evaluating statements about number operations

These activities for secondary mathematics lessons enable pupils to understand the properties of number operations and to substitute integers, fractions, decimals and negative numbers into statements and equations. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N3: Rounding numbers

These activities for secondary mathematics lessons enable pupils to round numbers to the nearest 10, 100 and 1000. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N5: Understanding the laws of arithmetic

These activities for secondary mathematics lessons enable pupils to interpret numerical expressions, recognise the order of operations and equivalent expressions, and understand the distributive laws of multiplication and division over addition. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N6: Developing proportional reasoning

These activities for secondary mathematics lessons help pupils reflect on the reasoning they currently use when solving proportion problems, appreciate the multiplicative structure of such problems, and create their own variants. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N7: Using percentages to increase quantities

These activities for secondary mathematics lessons enable pupils to make links between percentages, decimals and fractions, and to recognise the inverse relationship between increases and decreases. These activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N8: Using directed numbers in context

These activities for secondary mathematics lessons help pupils to understand and use directed numbers in the context of temperatures. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N9: Evaluating directed number statements

These activities for secondary mathematics lessons enable pupils to make valid generalisations about the effect of operations on directed numbers. These activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N10: Developing an exam question – Number

These activities for secondary mathematics lessons help pupils to use past examination questions creatively and to select and use appropriate techniques to solve problems involving numerical, graphical and algebraic manipulation. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N11: Manipulating surds

These activities for secondary mathematics lessons enable pupils to identify equivalent surds and to develop their ability to simplify expressions involving surds. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N12: Using indices

These activities for secondary mathematics lessons introduce pupils to fractional and negative indices and enable them to evaluate numerical expressions and use the rules of indices with integer and fractional powers of variables. The activities are part of the 'Standards units in number’ within ‘Teaching number’.

## Unit N13: Analysing sequences

These activities for secondary mathematics lessons enable pupils to define a sequence using the general form of the nth term, to define a sequence inductively, and to recognise and define arithmetic and geometric progressions. The activities are part of the 'Standards units in number’ within ‘Teaching number’.