1.1.5 · Maths › Arithmetic & Number Systems
Division ka jawab hota hai "kitne equal groups ban sakte hain, aur kitna bacha?"
Agar tumhare paas 17 toffees hain aur unhe 5 bachon mein baantna hai, toh har bacche ko 3 milenge (the quotient )
aur 2 toffees bach jaayengi (the remainder ). Division basically divisor ki repeated subtraction hai jab tak aur subtract na ho sake — long division usi repeated subtraction ka ek fast, organised tarika hai jo digit-by-digit kaam karta hai.
Long division, division algorithm ko ek baar mein ek place-value column par apply karna hai, sabse bade place se shuru karke. Kyunki 728 jaisa number 7 hundreds + 2 tens + 8 ones hota hai, hum pehle hundreds divide karte hain, bache hue ko tens mein carry karte hain, aur aage bhi aisa hi.
728 ÷ 6
Step 1 — hundreds divide karo. 7 ÷ 6 = 1 (likho 1 ), 1 × 6 = 6 , subtract karo: 7 − 6 = 1 bacha.
Kyun? Hum poochh rahe hain "7 hundreds mein kitne 6 s hain?" — ek hundred-group, 1 hundred bacha.
Step 2 — tens bring down karo. Bacha hua 1 hundred = 10 tens; 2 tens add karo → 12 . Divide karo: 12 ÷ 6 = 2 (likho 2 ), 2 × 6 = 12 , subtract karo → 0 .
Kyun? Bacha hua hundred, dah tens ban jaata hai — yahi "bring down" ka trick hai jo place value express karta hai.
Step 3 — ones bring down karo. 8 bring down karo. Divide karo: 8 ÷ 6 = 1 (likho 1 ), 1 × 6 = 6 , subtract karo → 2 .
Kyun? Ones column par same logic; 2 , 6 se chhota hai isliye ruk jaate hain.
Answer: quotient = 121 , remainder = 2 .
Check (hamesha karo!): 6 × 121 + 2 = 726 + 2 = 728 ✓
945 ÷ 7
9 ÷ 7 = 1 , rem 2 . Kyun: nine mein ek seven fit hota hai, do bacha.
Bring down 4 → 24 . 24 ÷ 7 = 3 , 3 × 7 = 21 , rem 3 . Kyun: 7 × 3 = 21 ≤ 24 < 28 .
Bring down 5 → 35 . 35 ÷ 7 = 5 , rem 0 .
Quotient = 135 , remainder = 0 . Check: 7 × 135 = 945 ✓. Remainder 0 matlab 7 , 945 ko exactly divides karta hai.
Worked example Divisor pehle digit se bada:
308 ÷ 4
3 ÷ 4 = 0 ? Hum group nahi bana sakte, isliye quotient ka hundreds digit 0 hoga — hum 30 dekhenge.
30 ÷ 4 = 7 , 7 × 4 = 28 , rem 2 . Kyun: 4 × 7 = 28 ≤ 30 < 32 .
Bring down 8 → 28 . 28 ÷ 4 = 7 , rem 0 .
Quotient = 77 , remainder 0 . Check: 4 × 77 = 308 ✓.
Recall Compute karne se pehle predict karo
Pehle 623 ÷ 8 estimate karo: 8 × 80 = 640 (zyada bada), 8 × 70 = 560 . Toh quotient 70 s mein hoga.
Ab compute karo: 62 ÷ 8 = 7 (rem 6 ), bring down 3 → 63 , 63 ÷ 8 = 7 (rem 7 ).
Quotient 77 , remainder 7 . Tumhara forecast (70 s) match hua — confidence bana, arithmetic slips pakde gaye.
Common mistake "Remainder divisor ke barabar ho sakta hai."
Kyun sahi lagta hai: agar r = d hai toh tumhare paas "ek poore group ki value" bacha, toh valid lagta hai.
Fix yeh hai: ek poore group ko quotient mein count karna zaroori hai . Agar r ≥ d hai, quotient mein 1 add karo aur d subtract karo. Remainder 0 ≤ r < d rehna chahiye. Jaise 17 ÷ 5 = 2 rem 7 likhna galat hai; 3 rem 2 karo.
Common mistake Placeholder zero bhool jaana.
Kyun sahi lagta hai: 308 ÷ 4 mein, pehle 7 phir 7 milta hai aur tum "7 " likhte ho ... leading step skip karna harmless lagta hai.
Fix yeh hai: jab bhi current running number divisor se chhota ho ek digit bring down karne ke baad , quotient mein 0 likhna zaroori hai agla digit bring down karne se pehle. Warna 6048 ÷ 6 galti se 1008 ki jagah 18 dega.
Common mistake Dividend aur divisor aapas mein badal dena.
Kyun sahi lagta hai: "5 into 17 " vs "17 into 5 " bolne mein similar lagte hain.
Fix yeh hai: dividend = bracket ke andar wali badi poori amount ; divisor = bahar wala group size. 17 ÷ 5 matlab 17 ko split karo, 5 ko nahi.
Mnemonic Long-division steps ka order
"Does McDonald's Sell Burgers?" → D ivide, M ultiply, S ubtract, B ring down. Repeat karo.
Recall Feynman: ek 12-saal ke bacche ko explain karo
Socho 728 marbles 6 boxes mein baantne hain. Pehle 100 ke bade bags baanto: har box mein 1 hundred daal sakte ho (6 hundreds use hue), 1 hundred bacha. Bacha hua hundred, tens mein todon, jo tens pehle se the unhe mila lo, phir wohi baanto, phir single marbles ke saath bhi aisa karo. Jo marbles evenly deal nahi ho sake woh remainder hain. Har box ko jo milta hai woh quotient hai, jo pile se shuru kiya woh dividend hai, aur boxes ki sankhya divisor hai.
a ÷ b = q rem r mein chaar division words kaun se hain?a =dividend, b =divisor, q =quotient, r =remainder.
Division Algorithm equation batao. Dividend = Divisor × Quotient + Remainder, with 0 ≤ r < divisor.
Remainder divisor se chhota kyun hona chahiye? Agar r ≥ divisor, toh ek aur poora group fit hoga, matlab quotient complete nahi tha.
728 ÷ 6 mein quotient aur remainder kya hain?Quotient 121 , remainder 2 (kyunki 6 × 121 + 2 = 728 ).
Long division ke 4 repeating steps? Divide, Multiply, Subtract, Bring down (DMSB).
Koi bhi long-division answer check kaise karte hain? divisor× quotient+ remainder compute karo; yeh dividend ke barabar hona chahiye.
Quotient mein 0 kab likhte hain? Jab ek digit bring down karne ke baad bhi running number divisor se chhota ho.
Remainder = 0 kya batata hai? Divisor, dividend ko exactly divide karta hai (dividend, divisor ka multiple hai).
Digit-sum rule 3 se divisibility kyun test karta hai? Kyunki 10 ≡ 1 ( mod 3 ) , ek number aur uska digit sum mod 3 par same remainder share karte hain.
Division = share into equal groups
Repeated subtraction of divisor
Quotient - number of groups
Division Algorithm a = dq + r
0 le remainder less than divisor
Long division, column by column
Place value, bring down trick
Check by multiplying back