Calculators feel precise. They aren't always. Knowing where errors creep in turns 'magic' answers into useful ones.
Calculators do the heavy lifting, but knowing what is going on underneath is what saves you money — or stress — later. Calculators feel precise. They aren't always. Knowing where errors creep in turns 'magic' answers into useful ones.
Computers can't represent some decimals exactly. 0.1 + 0.2 isn't exactly 0.3.
Result can never be more precise than inputs. Garbage in, garbage out, prettier.
Half-up, half-even, truncate. Different defaults can change cents on invoices.
Fitness tracker calorie counts are ±30%. Treat as trends, not facts.
Why doesn't my calculator agree with Excel? Different rounding, different precision, sometimes different formulas.
Should I trust scientific calculator results? For pure math, yes. For real-world inputs, accuracy is limited by your measurement.
If you only remember one thing from this post, make it that the inputs matter more than the calculator.