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Introducing spreadsheet calculation

Entering a formula with two operations (+/- only)

Numeracy Focus	Reasoning and generalising about numbers and shapes.
Learning Objectives	To be able to use a spreadsheet to solve a simple formula To learn how to copy formulae from one cell to another. To appreciate the effect of brackets in a mathematical operation.
Resources	Set up the large display if available. Make copies of the activity sheet for this lesson.
Key vocabulary	Cell, row, column, formula, reference, operation
Revision / oral	Begin with quick-fire questions focusing on two operations. Reinforce the idea of a start number: 'Start with 2. Add 6, subtract 3.' How is this done using a calculator? Can children compare a calculator display with a spreadsheet? The calculator can only display one value at a time, but the spreadsheet can display hundreds or even thousands of values on a grid.
Main activity	Enter the values 6 and 7 into A1 and A2. Show the class how to enter this formula in B1: Ask the class to predict the result. When Enter is pressed, the value 5 appears in B1. Show children how to copy B1 to B2. Ask the class, 'Why is it 6 now? Why hasn't it just copied 5?' Click on B2 to show that it contains =A2-4+3. Ask the class to explain what has happened. Now, try changing the formula to =A2-2+5. Again, ask children to predict what will happen when Enter is pressed. You could suggest changing the start values in A1 and A2. What do children think will happen? On the task sheet, children write formulas and results. Remind them to begin each formula with an equals sign. On the computers, children work in pairs to enter and copy formulae. They explore what happens if the start values are changed.
Support	Check for misunderstandings. Can the children talk through the example in the main activity, above? Give them another example to talk through with you, then ask them to invent their own.
Extension	Ask children to investigate multiplication combined with addition. Remind them that the computer uses an asterisk as a multiplication sign. Are the results always what they expected? They may go on to investigate the effect of inserting brackets, as in =A1*(4+3)
Plenary	If a large display is available, children's own formulas can be tested. Otherwise, write them on the board and ask the class what the result will be. Did anyone notice patterns in their results? Give the group investigating brackets a chance to report.

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