Maths One Shot for SSC CGL 2025 | SSC CGL & CHSL Maths Important Questions By Akshay Sir

Main ideas / lessons (what the speaker teaches)

• Focus on high-frequency Maths topics for SSC/CHSL/NTPC/CGL, especially:
  • Simplification, Percentages, Profit-Loss, Simple & Compound Interest
  • Time & Work, Speed-Time-Distance, Ratio
  • Mixture/Alligation, Number System, LCM/HCF
  • Algebra, Trigonometry, Mensuration, Geometry
• Follow a strong core exam strategy:
  • Practice expected question patterns
  • Use “tricks” for speed
  • Do not leave any question
• Adopt a method-first mindset:
  • If a question matches a known pattern, use the known transformation
  • Don’t start from scratch
• Repeated emphasis on repeatable shortcut rules, often described as:
  • “direct trick” / “format”

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Detailed methodology / instruction-style content (as presented)

1) Sum of natural numbers/multiples using pattern grouping

Example taught: sum of numbers from 1 to 100 that are multiples of 7.

Method:

• Identify multiples: 7, 14, 21, …, 98
• Use series-sum by grouping/trick
• Treat as a structured arithmetic progression and compute via transformation

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2) Adding series of fractions with the same denominator structure

Example taught: compute expressions like 991/7 + 992/7 + … + 996/7

Method:

• Separate integers and fractional part
• Count how many times the integer part repeats (e.g., 99 appears 6 times if there are 6 terms)
• Add integer part using multiplication (e.g., 99×6)
• Add the remaining fraction contribution

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3) Time & Work with pairwise work times (LCM-based)

Example taught:

• A + B completes in 18 days
• B + C completes in 27 days
• C + A completes in 54 days
• Find time for 50% of total work

Method (as taught):

• Take LCM of pair-work times:
  • LCM(18,27,54) = 54 → interpret it as total work = 54 units
• Convert each pair work to per-day work rates on that total:
  • A + B: 54 units in 18 days → 54/18 = 3 units/day
  • B + C: 54 units in 27 days → 54/27 = 2 units/day
  • C + A: 54 units in 54 days → 1 unit/day
• Infer individual contributions from the overlaps (pair sums correspond to double-counting individuals)
• For 50% completion:
  • 50% of 54 = 27 units
  • Compute the time taken by the combined effective work rate to produce 27 units (final result stated)

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4) Square-root extraction using identity (a^2 + b^2 \pm 2ab)

Example taught: extracting a square root from an expression containing ±2ab

Method:

• Use:
  • ((a+b)^2 = a^2 + b^2 + 2ab)
  • ((a-b)^2 = a^2 + b^2 - 2ab)
• Match the expression to the correct identity
• Then take the square root accordingly

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5) Least number divisible by multiple numbers + perfect square constraint

Example taught: least number divisible by 16, 20, 24 and also a perfect square

Method:

• Compute LCM(16,20,24) (given as 240 in the script)
• Convert prime factorization into even powers only:
  • Pair factors to make exponents even
  • Multiply remaining unpaired factors to reach the next perfect square
• Perfect-square result stated: 3600

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6) Discount on “packs” using effective selling price

Example taught:

• 1 bottle price = ₹240
• 4 bottles pack price = ₹768
• Find % discount on the pack

Method:

• Expected price for 4 bottles if sold individually:
  • 240×4 = ₹960
• Actual pack price = ₹768
• Discount = 960 − 768 = ₹192
• % discount = (192/960)×100 = 20% (final stated)

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7) Speed ratio vs time ratio (inverse proportion)

Method taught:

• If speeds are in ratio (v_1:v_2:v_3) and distances are the same:
  • time ratio = 1/v₁ : 1/v₂ : 1/v₃
• Warning:
  • Don’t treat “inverse” as merely “opposite” casually
  • You must take the reciprocal

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8) Tricky series / roots involving “carry/next step”

• Several mistake-prone series and root problems were taught with warnings like:
  • Be careful when adding numbers inside root and later removing root
• Many steps were framed as common exam pitfalls

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9) Profit/Loss questions like “18 articles for ₹1680”

Method taught:

• Profit = Selling Price − Cost Price
• If the framing implies equivalence like:
  • profit on 18 items = CP of 3 items
• Interpret using:
  • SP(18) − CP(18) linked to CP(3)
• Use ratio-based CP per item:
  • CP(18) = (CP per item)×18
• Final CP per item stated: ₹80 (option A mentioned)

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10) Percentage error questions

Method taught:

• If someone uses a wrong reciprocal factor:
  • Compute wrong result vs correct result difference
• Convert that difference into:
  • % of the correct value

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11) Mixtures / spirits concentration using unit multiplication

Example taught:

• 4 liters of 80% spirit + 6 liters of 50% spirit
• Find % spirit in the mixture

Method:

• Convert each component into spirit units (fraction × liters)
• Total spirit proportion:
  • Spirit amount = (fraction)×(liters)
• Percentage in final mixture:
  • (total spirit / total liters)×100
• Final stated as: 46%

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12) Successive discounts equivalence

Example taught: 30% then 20% then 10% successive discounts

Method:

• Convert each discount to the payable multiplier:
  • After 30%: pay 70% = 7/10
  • After 20%: pay 80% = 4/5
  • After 10%: pay 90% = 9/10
• Multiply payable fractions
• Total discount = 1 − payable fraction
• Final stated effective discount: 49.6%

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13) Average via “assumed average” / shifting method

Example taught: boys avg 62 kg, girls avg 55 kg with ratio 3:2

Method:

• Choose an assumed average (often the lower average)
• Compute extra over assumed average:
  • extra = (actual avg − assumed avg)
• Distribute extra across population by ratio
• Convert back to total average
• Final stated average: 59.2 kg

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14) Alternate work / alternating days using LCM and “tasks per day”

Method taught:

• Determine total work per LCM of work rates
• For alternating workers:
  • compute work done by the worker who works on a day
  • skip the next day for the other worker
• Often reduces to:
  • tasks done in one full cycle = A’s work on A-days + B’s work on B-days
• Final stated result for a specific question: 16 days (option B mentioned)

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15) Compound interest shortcut using consecutive years

Method taught:

• Use interest behavior over consecutive years
• When amounts at years 3 and 4 are known:
  • scale via constant year-over-year increase in compound comparisons
• Use proportionality to extend to 100
• Example results mentioned include:
  • interest rate 5% and 12.5% (as stated in different places)

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16) LCM trick for powers

Method taught:

• For expressions like:
  • 4^12, 4^18, 4^36, 4^24
• If asked for LCM:
  • LCM relates to the maximum power handling (as clarified by the speaker)
• Speaker also corrects misconceptions about “smallest vs greatest” power

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17) Prime counting between ranges by splitting known primes

Method taught:

• Use known counts up to 50 and 100:
  • primes 1–50 = 15
  • primes 50–100 = 10 (as referenced)
• Compute total primes in 1–100 by summation and options
• Final stated option: A

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Overall structure of the session

• Starts with:
  • topic list + schedule + exam relevance
• Then a long sequence of SSC-oriented questions
• For each question:
  • identify the pattern
  • apply a direct trick / standard identity
  • select the final option and emphasize conceptual clarity
• Ends with promotional guidance about joining Adda247 packs using code Y170, plus reminders to revise with PDFs and study plans.

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Speakers / sources featured

1. Akshay Awasthi / Akshay Sir (main teacher)
2. SSC Adda247 (channel/platform referenced)
3. Students/participants (referred to frequently as characters/learners, e.g., “kids”, “students”, names used for question context)