# 2.NBT.7. Add and subtract within 1000, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method. Understand that in a

A fun game to practise mental addition skills. The game was designed to cover all the mental addition objectives in the new math curriculum. You can choose one objective, or choose all the objectives for a year group.

This game, together with all the other crystal crash games, is available as a single iPad or Android app.

Subtraction - Crystal Crash

The game was designed to cover all the mental subtraction objectives in the new math curriculum. You can choose one objective, or choose all the objectives for a year group.

This game, together with all the other crystal crash games, is available as a single iPad or Android app.

 1) Subtract numbers from up to 10 (Y1) 6) Subtract from 100 (multiples of 10) (Y3) 11) Subtract tens from a three-digit number (Y3) 16) Subtract combinations of decimals (1dp) (Y4) 2) Subtract numbers from up to 20 (Y1) 7)Subtract from 100 (multiples of 5) (Y3) 12) Subtract hundreds from a three-digit number (Y3) 17) Subtract a decimal (2dp) from 1  (Y5 & Y6) 3) Subtract ones from a two-digit number (Y2) 8) Subtract from 100 (Y3 & Y4) 13) Subtract a decimal (1dp) from 1 (Y4 & Y5) 18) Subtract combinations of three-digit numbers (Y5 & Y6) 4) Subtract tens from a two-digit number (Y2) 9) Subtract from 1000 (multiples of 100) (Y3 & Y4) 14) Subtract a decimal (1dp) from 10 (Y4 & Y5) 19) Subtract combinations of decimals (2dp) (Y5 & Y6) 5) Subtract a two-digit number from a two-digit number (Y2) 10) Subtract ones from a three-digit number(Y3) 15) Subtract two-digit numbers from three-digit numbers (y4)

Shoot the spaceship with the correct answer and dodge the incoming fire. A fun game to practise a wide range of key mathematical skills.

There are over a hundred carefully differentiated levels linked to objectives from the new maths curriculum. The game can be used to teach: Multiplication, Addition, Reading Numbers, Subtraction, Fractions of Numbers, Roman Numerals, Rounding Numbers, Division, Converting Fractions to Decimals, Converting Fractions to Percentages, Telling the Time in Words, Recognising Multiples, Factors, Prime, Square and Cube Numbers, and Simplifying Fractions. A full list of levels is below. This game is also available as an iOS and Android app.

Drag the digits to make a given sum. Lots of choice over level. A great starter activity for discussions on place value, mental methods of calculations and problem solving.

Number Bonds (2)

Designed to help children to visualise and understand number bonds to 20, 50 and 100. Numbers are represented on a number line and using base-ten blocks.

This game is now part of the 'Calculations' collection, which includes the following 17 games and resources: Column Addition, Expanded Addition, Expanded Addition - Place Value Counters, Number Bonds(2), Addition - Digit Drag, Missing Symbols, Column Subtraction, Column Subtraction using Place Value Counters, Counting on to find difference on a beadstring, Multiplication Grid Method, Multiplication Written Method, Ratio and Scaling Numbers, Representing Multiplication, Division by Chunking Up, Division by Chunking Down, Formal Written Division - Round Up or Down?, Short Division Writen Formal Method.

The Calculations app is available on Google Play and the App Store.

Balancing Sums

An excellent tool for reinforcing an understanding of the role of the equals sign. Choose one objective, or many. You can choose all the objectives for a single year group (or multiple year groups). You can also choose to balance between different types of calculations (eg addition and multiplication).

Difference using a marked number line

Count on from the smaller number to the larger. As numbers are added to the balance scale they are also shown on the number line. Children should be encouraged to use their knowledge of number bonds to develop efficient mental methods.

Levels include counting up to 10, 20, 50 or 100, finding the difference between 2-digit numbers and decimals.

Difference using an unmarked number line

Find the difference between two numbers by counting on from the smaller number to the larger number. Children must add the fewest numbers possible, so are encouraged to develop more efficient mental methods. The addition is also shown as jumps on a number line.

Levels include counting up to 10, 20, 50 or 100, finding the difference between 2-digit numbers, 3-digit numbers and decimals.

Number Bonds

October 2012: New game added in which number bonds are represented visually using base-ten blocks and a number line.

Find pairs of numbers with a given total. Play against the clock.

Expanded Addition using Place Value Counters

A step towards a more formal written method of columnar addition.

This game is now part of the 'Calculations' collection, which includes the following 17 games and resources: Column Addition, Expanded Addition, Expanded Addition - Place Value Counters, Number Bonds(2), Addition - Digit Drag, Missing Symbols, Column Subtraction, Column Subtraction using Place Value Counters, Counting on to find difference on a beadstring, Multiplication Grid Method, Multiplication Written Method, Ratio and Scaling Numbers, Representing Multiplication, Division by Chunking Up, Division by Chunking Down, Formal Written Division - Round Up or Down?, Short Division Writen Formal Method.

The Calculations app is available on Google Play and the App Store.

Number Facts Beat The Clock

Score as many points as you can before the time runs out. A number of levels including addition, subtraction, multiplication, division and matching fractions and decimals.

*Updated 30th May 2013 - choose multiple objectives, or objectives grouped by national curriculum level. The game also now includes a scoreboard. An iPad version is also available.

Placing Calculations on a Number Line

Place the answer to calculations on a number line. An enormous array of choice. Addition, subtraction, multiplication and division. Ranging from adding numbers to 10 to multiplying 4 digit numbers. Great for combining teaching calculations and approximations with developing an understanding of place value.

Add the partitioned numbers beginning with the largest. Choice of 2-digit, 3-digit or 4-digit numbers. An important conceptual step before a more formal method of column addition.

This game is now part of the 'Calculations' collection, which includes the following 17 games and resources: Column Addition, Expanded Addition, Expanded Addition - Place Value Counters, Number Bonds(2), Addition - Digit Drag, Missing Symbols, Column Subtraction, Column Subtraction using Place Value Counters, Counting on to find difference on a beadstring, Multiplication Grid Method, Multiplication Written Method, Ratio and Scaling Numbers, Representing Multiplication, Division by Chunking Up, Division by Chunking Down, Formal Written Division - Round Up or Down?, Short Division Writen Formal Method.

The Calculations app is available on Google Play and the App Store.

Balancing Scales g and kg

Add weights to either pan until they are balanced. Can be used to teach addition, subtraction, partitioning, and mass, as well as developing an understanding of the equals sign.

Choose from grams, whole kilograms or kilograms with either 1 or 2 decimal places.

Balance scales - add, move or remove a weight

Balance the scales by adding, moving or removing a weight. A great mental starter to develop addition and subtraction skills.

Sequences

Find the correct number in a sequence. Lots of choice over level, count forwards or back, count in whole numbers, multiples of 10, multiples of 100, decimals and fractions.