Mental computation is the process of drawing on known strategies to solve an arithmetical problem. As a process it differs from mental arithmetic where the emphasis is on fast recall of known number facts, rather than having a way of working out what the answer might be. For example, to find 17+8, a strategic approach would be to split the 8 into 3+5 because you know that you can no bridge through 10 to reach the answer of 25.

This downloadable PDF resource suggests activities that support mental computation by exploring the Middle Primary Natural Maths Strategies posters. The posters present the strategies such as Bridging through 10, Compensating and Number Splitting as well as representations such as Chunking, the Open Number Line and Zigzag. Knowledge of these strategies and representations ensures that, in a situation where memory fails or the numbers are too large, the individual has the confidence to use mental computation to derive the answer.

This resource includes:

• 18 Natural Maths Strategies posters in colour in A4
• 16 resource cards

Topics include:

• Bridge Through
• Bridge Back Through
• Rainbow Facts
• Landmark Numbers
• Number Splitting
• Chunking for Addition
• Open Number Line for Addition
• Zigzag for Addition