Theory
60% or 6000%?
Meera's margin on sugar is 0.6, meaning sixty percent. She selects the cell, clicks the % button hoping to see 60%, and instead sees... 60%. Perfect.
Her cousin tries the same on a different cell: he types 60, clicks %, and Excel shows 6000%.
Same button, opposite result. The difference is understanding what percent style actually does to a number, and it does something surprising. This lesson is about look versus reality.
Theory
A costume, not surgery
Number formatting is a costume the value wears, not surgery on the value itself. Dress 0.6 as a percentage and it appears as 60%, but underneath it is still 0.6. Dress 1200000 with commas and it reads 12,00,000, still the same number. Change the costume all you like; the person underneath never changes. Every formula keeps using the real value, not the costume.
At a glance
The formatting buttons
| Format | Stored value | Displayed as |
|---|---|---|
| Percent style | 0.6 | 60% |
| Comma style | 1200000 | 12,00,000 |
| Currency (rupee) | 450 | Rs 450.00 |
| Increase decimal | 2.618 | 2.62 (rounded display) |
| Decrease decimal | 2.618 | 3 (rounded display) |
Theory
Percent style: the times-100 rule
Percent style does two things to the display: multiplies it by 100 and adds a % sign.
So to show 60%, you must store 0.6 (because 0.6 × 100 = 60). Store 60 and you will see 6000%.
The rule: a percentage lives in the cell as its decimal fraction. Half is 0.5, three-quarters is 0.75. This matches the maths: 60% literally means 60/100 = 0.6. The button just handles the display arithmetic for you.
Quiz
Meera types 0.25 in a cell and clicks Percent Style. What does the cell display?
- 25%
- 0.25%
- 2500%
- 25
Show the answer
25%
Percent style multiplies the displayed value by 100 and adds %, so 0.25 shows as 25%. The classic trap is the reverse: a student wanting 25% types 25, clicks the button, and gets 2500%. Rule to memorise: store the decimal fraction (0.25 for 25%), and let the button dress it.
Think first
The rounding illusion
Meera has 2.4 and 2.4 in two cells and clicks Decrease Decimal until both show 2. She sums them in a third cell (also formatted to show no decimals). The sum cell shows 5, not 4. Take five seconds: how?
Show the answer
Decrease Decimal only rounds the display, not the stored value. The two cells still hold 2.4 each; their real sum is 4.8, which rounds for display to 5. The eye sees 2 + 2 = 5 and panics, but the maths used the true 2.4 values. Lesson: formatting never changes what a formula computes with. Read the formula bar to see the truth.
Watch out
Where marks leak
Believing decimal buttons round the value, they round the display only; formulas still use full precision (the 2.4 + 2.4 = 5 illusion). Storing 60 instead of 0.6 for a percentage. And assuming formatting is permanent maths, it is reversible dressing: strip the format and 0.6 is right there. If you truly need to round the stored value, that is the ROUND() function, not the decimal button (a distinction exams reward).
Theory
Real reports depend on this
GST invoices, salary slips and bank statements all rely on this display-versus-value split: the paper shows tidy rounded rupees while the system keeps full paise underneath, which is why totals sometimes look "off by one". When you build reports in your BCA project, remember: format for humans, compute on the real numbers. Next: adding pictures, shapes and headers so Meera's sheet can be printed as a proper price list.
Summary
Key takeaways
- Formatting changes how a value LOOKS, never what it IS (a costume, not surgery).
- Percent style multiplies the display by 100 and adds %: store 0.6 to show 60%.
- Comma style groups thousands; currency adds a symbol like the rupee.
- Increase/Decrease Decimal round the DISPLAY only; the stored value keeps full precision.
- Rounded displays can make sums look wrong (2.4 + 2.4 shows as 5); use ROUND() to change the real value.
- Memory hook: the number wears a costume; formulas see the person underneath.