Simplification & Approximation — IBPS PO Quantitative Aptitude

Simplification is where you make your time in the quant section, not spend it. In Prelims, 5–10 of the 35 questions are pure simplification or approximation — no word problem, no chart, just "solve this expression". Each should take 20–30 seconds, which means this block alone can bank 8–10 near-certain marks and hand you the extra minutes the DI sets demand. The whole chapter is BODMAS discipline plus a small kit of arithmetic shortcuts. Learn the kit; the marks follow.

1. What IBPS actually asks

Two question types, nearly identical in method:

• Simplification — an exact expression to evaluate: $\frac{3}{4}\times 120+15\%\text{ of }240-\sqrt{196}$. The answer is exact and sits in the options.
• Approximation — the numbers are deliberately "ugly" and the instruction is to find the nearest value: $47.9\%\text{ of }801+12.02\times 15.98\approx ?$. You round first, compute second.

Also common: missing-number ("$?\times 12=480-120$") and quadratic-flavoured single expressions. All of them reward the same fluency.

2. BODMAS — the one rule that must be automatic

Order of operations, always: Brackets → Orders (powers/roots) → Division & Multiplication (left to right) → Addition & Subtraction (left to right).

The classic IBPS trap is the "of" operator and the left-to-right rule for ÷ and ×:

• "$\frac{3}{4}$ of 60" is a multiplication done at the multiplication stage — but written as "of", candidates do it too early or too late.
• $48÷6\times 2$ is $(48÷6)\times 2=16$, not $48÷(6\times 2)=4$. Same-priority operators go strictly left to right.

Ninety percent of simplification errors are BODMAS-order slips, not arithmetic. Slow down for one second on the order; the numbers themselves are easy.

3. The fraction–percentage table (memorise once, use forever)

Every fast solver converts percentages to fractions on sight:

Extensions are free: $\frac{3}{8}=37.5\%$, $\frac{5}{8}=62.5\%$, $\frac{7}{8}=87.5\%$. "Find 87.5% of 640" is $\frac{7}{8}\times 640=560$ — a 3-second read, not a multiplication.

4. The squaring & multiplication kit

Bank these so the arithmetic never slows you:

• Squares up to 30 and cubes up to 15. They appear constantly in roots and quadratics; $\sqrt{529}=23$ should be instant.
• Multiply by 11: add adjacent digits. $52\times 11=5(5+2)2=572$.
• Numbers near 100: $96\times 97$ — base 100, deficits 4 and 3: $(96-3)|(4\times 3)=93|12=9312$.
• ×5, ×25, ×125: multiply by 10/2, 100/4, 1000/8. $84\times 25=\frac{8400}{4}=2100$.
• Squares ending in 5: $35^2=(3\times 4)|25=1225$.

$a^2-b^2=(a+b)(a-b),(a\pm b{)}^2=a^2\pm 2ab+b^2$

These two identities collapse many "simplify" expressions: $\frac{87^2-13^2}{74}=\frac{(87+13)(87-13)}{74}=\frac{100\times 74}{74}=100$.

5. Approximation — round, then compute

For approximation questions the options are far apart, so precision is wasted:

• Round each term to a clean number: $47.9\%\to 48\%\approx \frac{1}{2}$; $801\to 800$; $12.02\times 15.98\to 12\times 16=192$.
• $\frac{1}{2}\times 800+192=400+192=592$ → pick the nearest option.
• Roots: $\sqrt{626}\approx 25$ (since $25^2=625$); $\sqrt[3]{1330}\approx 11$ (since $11^3=1331$).
• Percentages of "ugly" bases: $18.03\%$ of $449\approx \frac{18}{100}\times 450=81$.

The instruction literally says "approximate value". Rounding is not cutting corners here — it is the intended method.

6. Missing-number & simple equations

"$?=15\%\text{ of }640+\sqrt{1024}-6^2$" → $96+32-36=92$. Read the expression, apply BODMAS, done. For "$?\%$ of 250 = 60", flip it: $?=\frac{60}{250}\times 100=24$. Keep the unknown isolated and treat it as one-step algebra.

8. The 25-second protocol

For every simplification/approximation question:

1. Scan for BODMAS order — spot "of", brackets, and ÷/× runs before computing.
2. Convert percentages to fractions and round (if approximation).
3. Reach for an identity ($a^2-b^2$, squares-of-5) if you see near-equal terms.
4. Compute left to right, keeping the unknown isolated.
5. If it isn't falling out in ~25 seconds, you've missed a fraction or an identity — re-scan once, else move on.