1. Step-Book With Professor Assessor © www.icoachmaths.co.uk 2015

2. What’s It All About? You are going to learn: How to add and subtract large numbers using written methods © www.icoachmaths.co.uk 2015

3. Recap on Place Value Remember – the position of a digit changes its value! Read these numbers: 10 units = 1 ten 10 tens = 1 hundred 10 hundreds = 1 thousand etc © www.icoachmaths.co.uk 2015 Thousands HundredsTensUnitsHundredsTensUnits 351 32709 756150 Our decimal number system is based on the number 10…

4. 800905 706 There are lots of ways to do this, but you MUST think about the place value of each digit and how they are connected: Example 895 + 76 Split the numbers up: Add the parts: Written Addition © www.icoachmaths.co.uk 2015 800 90 5 +11 70 6 +160 800 = 971

5. Traditional written addition does the same thing but is more compact and does not have as many steps: Example 895 + 76 Line the numbers up – units with units etc: Add the parts: 895 76 Written Addition © www.icoachmaths.co.uk 2015 1 7 9  1 1

6. Example 1398 + 579 Written Addition © www.icoachmaths.co.uk 2015 1398 579  9 7 7 1 1 1 300 90 8 70 9 1000 500 OR 1000300908 500709 1000+800+160+17 = 1977

7. © www.icoachmaths.co.uk 2015 532 + 65 63 + 51 234 + 97 7165 + 4367 372 + 456 103 + 5428 Your turn Try these: Check your answers with a calculator …

8. Again, there are different ways to do this, but you MUST think about the place value of each digit and how they are connected: Example 895  76 Split the numbers up: Subtract the parts: 8008015 706 Written Subtraction © www.icoachmaths.co.uk 2015 800 8015 +9 706 +10 800 = 819 Why do we need to have 80 and 15 not 90 and 5…?

9. Again, traditional subtraction follows this idea BUT is more compact with less steps: Example 895  76 Line the numbers up – units with units etc: Subtract the parts: 1010 Written Subtraction © www.icoachmaths.co.uk 2015 895 76  8 91 8

10. 1010 Example 1396  479 1010 Written Subtraction © www.icoachmaths.co.uk 2015 1396 479  9 1 7 1300 80 16 70 9 400 OR 13008016 400709 = 917 8 900 +10 +7 0

11. © www.icoachmaths.co.uk 2015 532  65 463  251 234  97 7165  4367 872  416 5428  103 Your turn Try these: Check your answers with a calculator …

12. The End © www.icoachmaths.co.uk 2015 Sayonara…