You knew that question. The answer key still said wrong. A silly mistake is almost never a maths mistake. We read 180 wrong answer choices from our own question bank and sorted each one by hand. Only 10 were a slip in the sum. 118 came from reading the question wrong. More practice will not fix that. A fixed way of reading will.
Your sum was right. You solved the wrong sum.
The four steps, in order
- Read it again. What is given? What do they want?
- Look at the options. Which ones cannot be true?
- Find the way. How do you get from given to wanted?
- Check it. Put your answer back into the question.
One question that proves it
Here is a question from our own bank. We write these to the exam's pattern — they are not past paper questions. Read it slowly.
A train 200 metres long runs at 72 km/hr. How long will it take to cross a platform 160 metres long?
Four of the five choices are wrong. Here is the sum behind each one.
| Answer | The sum done | What it means |
|---|---|---|
| 2 s | (200 − 160) ÷ 20 | Took the platform away instead of adding it |
| 8 s | 160 ÷ 20 | Used the platform. Forgot the train. |
| 10 s | 200 ÷ 20 | Used the train. Forgot the platform. |
| 5 s | 360 ÷ 72 | Did not change km/hr into metres per second |
| 18 s | 360 ÷ 20 | Train plus platform, both in metres |
Question itm_fb9f52634da1974b, IBPS PO Prelims bank. All five sums recomputed 25 August 2026. Speed: 72 km/hr = 72 × 1000 ÷ 3600 = 20 metres per second.
Every one of those four sums divides correctly. The mistake sits before the sum.
Take the last one. The distance is in metres. The speed is in km per hour. A unit is what you measure in — metre, second, rupee. Two different units cannot go into one sum.
Where the marks really go
Our IBPS PO bank has 45 word problems in the maths section. Each has four wrong choices. Each wrong choice carries a short note. The note says what picking that choice means.
That is 180 notes. We read every one by hand. Then we sorted each one.
| What went wrong | Of 180 |
|---|---|
| Used the wrong rule | 52 |
| Used a wrong given, or dropped one | 51 |
| Solved for the wrong person or thing | 40 |
| Worked out a middle value and stopped | 22 |
| Slip inside the sum | 10 |
| Did not change the unit | 5 |
The 180 wrong answer choices on the 45 word problems in the maths section of our IBPS PO Prelims bank. The full bank is 3 papers, 300 questions and 1,200 notes. All 180 notes were read and sorted by hand on 25 August 2026, not matched by keyword. Sorting is a judgement, so treat the split as close, not exact.
The first four rows are reading faults. Only the last two are maths faults.
Read the "slip inside the sum" row again. Only 10 of 180. That is 1 in 18.
So the thing you call a silly mistake is mostly not one. It is a reading mistake in a maths coat.
Why do I make silly mistakes in exams?
Because you read for the numbers, not for the question.
Your eyes find 200, 72 and 160. Your hand starts moving. But cross a platform is a given too, and it holds no number. Miss it and the rest is neat, fast and wrong.
That is why step 1 has a small task inside it. Say the question again with no numbers in it. A train has to fully cross a platform. How long does that take? If you cannot say it, you have not read it.
No time to read it twice?
You do have time. Look at what one wrong answer costs.
| Exam | Right | Wrong | You lose |
|---|---|---|---|
| SSC CGL Tier 1 | +2.00 | −0.50 | 2.50 |
| IBPS PO Prelims | +1.00 | −0.25 | 1.25 |
Marking pattern taken from the SSC and IBPS 2026 notices. Always check the notice for your own exam year.
Both exams take marks away for a wrong answer. That is called negative marking. On a question you knew, you miss the mark and pay the penalty. So the gap is 2.00 + 0.50 in SSC CGL, and 1.00 + 0.25 in IBPS PO.
Eight silly mistakes in SSC CGL Tier 1 cost you 20 marks. Six cost you 15.
Now the clock. You get 60 minutes for 100 questions. That works out at 36 seconds each. It is an average, not a rule. Easy ones take you less. Hard ones take you more.
Reading the question again costs you seconds. Getting it wrong costs you 2.50 marks.
Your exam is not the other exam
SSC CGL and IBPS PO look alike. They are not. Find the row for your own exam.
| SSC CGL Tier 1 | IBPS PO Prelims | |
|---|---|---|
| Questions | 100 in 60 min | 100 in 60 min |
| Options | 4 | 5 |
| Right answer | +2.00 | +1.00 |
| Wrong answer | −0.50 | −0.25 |
| Tick 100 with no idea | +12.5 marks | 0 marks |
Last row worked out. SSC CGL: 25 right × 2 = 50, and 75 wrong × 0.50 = −37.5, which leaves +12.5. IBPS PO: 20 right × 1 = 20, and 80 wrong × 0.25 = −20, which leaves 0. Pattern from the SSC and IBPS 2026 notices.
Read that last row as maths, not as advice. Do not go and tick 100 boxes. It is there to show you how little guessing pays. A wild tick is worth nothing in IBPS PO. In SSC CGL it is worth a little. Fixing eight silly mistakes is worth 20 marks. That is the bigger number, and it is the one you control.
The one-week count
Do this for seven days. It costs you nothing.
- Mark every wrong answer. Write one number next to it: 1, 2, 3 or 4. Which step failed?
- Wait for about 30 of them. Do not judge it early. Let them collect.
- Count each number. Your own pattern shows up. For most people it is step 1.
Now you know where your marks go. Learning more formulas will not help if they go at step 1.
Find your own step 1
Take a full mock. Every wrong choice tells you what it means, so you can count your steps.