Spreadsheets: formulas and modelling
Computer Science · Key Stage 2 · The School
References, not numbers
Type =B2*C2 rather than =3*4. A formula built from cell REFERENCES updates itself when the numbers change, which is the entire point of a spreadsheet. Typing numbers into formulas turns a live model into a dead sum, and it is the most common beginner mistake.
The four functions to know first
=SUM(B2:B10) adds a range. =AVERAGE(B2:B10) means it. =MAX(B2:B10) finds the largest. =IF(B2>10,"over","under") makes a decision. Between them these four cover most of what a spreadsheet is asked to do at school and a surprising amount of what it is asked to do at work.
Modelling: change one thing
Build a party budget: guests, cost per guest, formula for the total. Now change the number of guests and watch everything update. That is a MODEL — a small copy of reality you can ask "what if?" questions of. Businesses and scientists use exactly this, with more rows.
Cells A1 to A5 hold 10, 10, 10, 10, 10. In B1 TYPE 50. In B2 write =SUM(A1:A5), which also shows 50. They look identical. Now change A1 to 20. B1 still says 50 and is now wrong; B2 updates to 60. That is the entire difference between a table and a MODEL — and it is why you can then ask "what if the price rose 10%?" and get an answer instead of retyping.