β Pehle Yeh Aata Hai?
Yeh post shuru karne se pehle, in teen sawaalon ko 1 minute mein khud try kijiye:
- 25 Γ 23 = 2?
- (32)4 = 3?
- 50 = ?
Answers dekho
- 8 (exponents jodo)
- 8 (exponents guna)
- 1
Teeno sahi? Badhiya, aage chaliye! Koi galat hua? Koi baat nahi, Post 3 β Exponent Ke Niyam: Guna Aur Power aur Post 5 β Zero Aur Negative Exponent dobara dekh lijiye.
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π¬ Kahani: Meenu Ki Chunauti: 230 Ya 320?
Meenu ne board pe likha: 230 aur 320 β kaun bada? Shart: calculator nahi, aur poora number nikaalna bhi nahi! π
Golu: β230! Exponent 30 bada hai na.β Meenu: βAur 3 base bada haiβ¦β
Dono ke paas ek-ek βtaakatβ hai. Is post mein hum aise hi tricky sawaalon ke pakke tareeke seekhenge, aur yeh chunauti bhi jeetenge. π
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π Concept: Tricky Sawaal Ke 4 Hathiyaar
π‘ Is post ki ek badi baat: Powers ke tricky sawaal mein pehle same base ya same exponent banao. Jab ek cheez barabar ho, to doosri dekh ke faisla turant. Exponent ke niyam isi ke auzaar hain.
Step 1: Hathiyaar 1: Compare karna
Tareeka A (same exponent): 230 = (23)10 = 810, aur 320 = (32)10 = 910. Ab exponent same (10), base 9 > 8 β 320 bada β
Tareeka B (same base): 85 vs 47: 85 = 215, 47 = 214 β 85 bada.
WHY kaam karta hai? Same base (1 se bada) β bada exponent = zyada baar guna = bada number. Same exponent β bada base har baar bada guna = bada number.
Kab kaunsa? Base ek doosre ki power hon (2, 4, 8, 16) β Tareeka B. Exponents ka common factor ho (30, 20 β 10) β Tareeka A.
Step 2: Hathiyaar 2: Units digit ka chakra
7 ki powers ke aakhri ank: 7, 49, 343, 2401, 16807β¦ β 7, 9, 3, 1, 7, 9, 3, 1β¦
WHY chakra? Units digit sirf pichle units digit pe depend karta hai (7 Γ 1 = 7 phir se shuru). Sirf 10 possible ank, to chakra banna hi hai.
745: chakra lambaai 4; 45 = 4 Γ 11 + 1 β 1st position β 7.
| Base ka units | Chakra | Lambaai |
|---|---|---|
| 2 | 2, 4, 8, 6 | 4 |
| 3 | 3, 9, 7, 1 | 4 |
| 4 | 4, 6 | 2 |
| 9 | 9, 1 | 2 |
| 0, 1, 5, 6 | wahi rehta | 1 |
Step 3: Hathiyaar 3: Hamesha / Kabhi-kabhi / Kabhi nahi
- βam Γ an = am+nβ β hamesha (gin ke saabit).
- β2n even haiβ β kabhi-kabhi: n β₯ 1 pe haan, par 20 = 1 odd!
- β(a + b)2 = a2 + b2β β kabhi-kabhi (sirf jab a ya b = 0). Kyun? Book 1 Ch 6 β (a + b)Β² Ka Formula mein.
- β5n ka units digit 0β β kabhi nahi.
WHY yeh tareeka? βHameshaβ ke liye wajah chahiye; βkabhi nahiβ/βkabhi-kabhiβ ke liye ek counter-example kaafi.
Step 4: Hathiyaar 4: Ginti (codes aur combinations)
4-ank ka PIN (0β9): har jagah 10 choice β 104 = 10,000. 5 ank β 105.
WHY? Har nayi jagah pichle saare options ke saath judti hai: Γ 10 (Post 4 β Combinations Aur Powers).
πͺ Atak Gaye? Aise Socho
- Pehle dono powers ke base factorise karo: 4 = 22, 8 = 23, 27 = 33.
- Same base ban gaya? Exponent compare karo. Nahi? Exponents ka HCF lo aur same exponent banao.
- Units digit ke liye pehle 4β5 powers likh ke chakra dhundho.
- Exponent ko chakra ki lambaai se bhaag do; shesh (remainder) = position (shesh 0 = aakhri).
- βHameshaβ bolne se pehle 0, 1, negative aur fraction pe test karo.
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π Deep Concept: Ek Cheez Barabar Karo: Tulna Ka Raaz
Do cheezein jinki do-do βtaakatβ alag hon, unki seedhi tulna mushkil. Jaise: 3 kg βΉ150 wala aam vs 2 kg βΉ110 wala. Hum kya karte hain? 1 kg pe laate hain (ek cheez barabar)!
Powers mein bhi yahi: base aur exponent dono alag β kuch nahi pata. Ek ko barabar karo (same base ya same exponent), phir faisla saaf.
Isliye exponent ke niyam itne kaam ke: (am)n = amn se 230 ko 810 bana sake. Niyam = roop badalne ka auzaar, number wahi.
Base < 1 ho to ulta! (1/2)3 = 1/8 < (1/2)2 = 1/4. Bada exponent = chhota number. Isliye βhameshaβ bolne se pehle fractions check karo.
Unifying idea: ek cheez barabar karo, phir doosri compare karo. Yahi ratio, fractions aur percentage ki tulna mein bhi hota hai. π―
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βοΈ Solved Examples
Example 1 (Easy): Kaun bada: 512 ya 118?
Exponents 12, 8 ka HCF 4. 512 = (53)4 = 1254. 118 = (112)4 = 1214.
125 > 121 β 512 bada.
Check: 512 = 24,41,40,625; 118 = 21,43,58,881 β
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Example 2 (Medium): 350 ka units digit?
Chakra: 3, 9, 7, 1 (lambaai 4). 50 = 4 Γ 12 + 2 β 2nd position β 9.
Check: 32 = 9, 36 = 729 (6 = 4 + 2), dono 9 pe khatam β
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Example 3 (NCERT style): Hamesha, kabhi-kabhi ya kabhi nahi: βn2 > nβ
n = 3: 9 > 3 β . n = 1: 1 = 1 β. n = 1/2: 1/4 < 1/2 β.
β Kabhi-kabhi (n > 1 ya n < 0 pe sach).
Check: n = β2: 4 > β2 β , to negative pe bhi sach β
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Meenu ki chunauti: 230 = 810, 320 = 910 β 320 bada! (Asal: 230 β 107 crore, 320 β 349 crore, 3 guna se zyada.) Golu ka βbada exponent jeetegaβ galat nikla. π
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π Real Life Mein Yeh Hathiyaar
- π Password: 6-ank PIN = 106 = 10 lakh options; letters bhi ho (36 choice) to 366 β 2 arab! Isliye mixed password zyada surakshit.
- π Number plate: βMH 12 AB 1234β jaise patterns: letters 262 Γ ank 104 = 67.6 lakh plates har zile ke liye.
- π Hafte ka din: din ka chakra 7 ka. Aaj ravivaar, to 100 din baad? 100 = 7 Γ 14 + 2 β mangalvaar. Units digit jaisa hi chakra!
- π Offer compare: β2 ka 3 gunaβ vs β3 ka 2 gunaβ jaisi tulna: ek cheez barabar karo.
- πΎ Memory: 1 GB = 230 byte β 109; isliye phone ke β64 GBβ mein thoda kam dikhta hai.
Chakra, ginti, tulna: teeno roz ke kaam mein chhupe hain.
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π§ Kab Use Karein, Kab Nahi
| Situation | Kya karein | Kyun |
|---|---|---|
| Base ek doosre ki power (2, 4, 8) | β Same base banao | Exponent dekho |
| Exponents ka HCF (30, 20) | β Same exponent banao | Base dekho |
| Bahut badi power ka aakhri ank | β Units digit chakra | Shesh = position |
| βHameshaβ daava | β Counter-example dhundho | 0, 1, fraction |
| Options ki ginti | β Choices ka guna | 10 Γ 10 Γ 10β¦ |
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βββ Worked Mistake
Sawaal: 240 aur 520 mein kaun bada?
β Galat: βBase 5 bada β 520β ya βexponent 40 bada β 240β β sirf ek taakat dekhi.
β Sahi: 240 = (22)20 = 420. Ab 420 vs 520 β 520 bada. Check: 240 β 1.1 Γ 1012, 520 β 9.5 Γ 1013 β
Doosri galti (units digit): 744 ka units digit: 44 Γ· 4 shesh 0 β β0th positionβ? Nahi! Shesh 0 = aakhri position β 1.
π§ Rule of thumb: Pehle ek cheez barabar karo (base ya exponent), phir doosri compare karo. Shesh 0 = chakra ka aakhri ank.
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π 10 MCQs
Q1. Kaun bada: 2ΒΉβ°β° ya 4β΄βΉ?
Solution dekho
Sahi jawab: (a)
- (a) sahi: 4β΄βΉ = 2βΉβΈ, aur 2ΒΉβ°β° = 4 Γ 2βΉβΈ bada β
- (b) galat: 4β΄βΉ = 2βΉβΈ hai, jo 2ΒΉβ°β° se chhota.
- (c) galat: 2ΒΉβ°β° β 2βΉβΈ, barabar nahi hain.
- (d) galat: Same base banane se turant pata chalta hai.
Q2. 2β΄Β³ ka units digit?
Solution dekho
Sahi jawab: (c)
- (a) galat: 43 Γ· 4 shesh 3, pehli position nahi.
- (b) galat: Shesh 3 hai, 2nd position nahi.
- (c) sahi: Chakra 2, 4, 8, 6 β shesh 3 β 8 β
- (d) galat: 6 aakhri position (shesh 0) pe aata.
Q3. βaβ° = 1β (a β 0) haiβ¦
Solution dekho
Sahi jawab: (a)
- (a) sahi: Har non-zero a ke liye sach β
- (b) galat: Koi counter-example nahi hai yahan.
- (c) galat: 5β° = 1, to βkabhi nahiβ galat.
- (d) galat: 2β°, 7β° sab 1 hain, sirf 1 nahi.
Q4. 3-ank ka code (har ank 0β9): kitne options?
Solution dekho
Sahi jawab: (d)
- (a) galat: 3 Γ 10 joda; guna karna tha.
- (b) galat: Yeh 2-ank ke codes ki ginti hai.
- (c) galat: 000 bhi ek code hai, use bhi gino.
- (d) sahi: 10 Γ 10 Γ 10 = 1,000 β
Q5. Kaun bada: 3β΄β° ya 4Β³β°?
Solution dekho
Sahi jawab: (a)
- (a) sahi: (3β΄)ΒΉβ° = 81ΒΉβ° > (4Β³)ΒΉβ° = 64ΒΉβ° β
- (b) galat: 64ΒΉβ° chhota hai 81ΒΉβ° se.
- (c) galat: 81 aur 64 barabar nahi hain.
- (d) galat: HCF 10 lekar same exponent banao.
Q6. (1/2)β΅ aur (1/2)Β³ mein kaun bada?
Solution dekho
Sahi jawab: (b)
- (a) galat: 1/32 chhota hai 1/8 se.
- (b) sahi: 1/8 > 1/32: base < 1 pe bada exponent chhota β
- (c) galat: 1/8 aur 1/32 barabar nahi.
- (d) galat: Powers kabhi 0 nahi banti yahan.
Q7. 9ΒΉβ΅ ka units digit?
Solution dekho
Sahi jawab: (a)
- (a) sahi: Chakra 9, 1; 15 odd β 9 β
- (b) galat: 1 sirf even power pe aata hai.
- (c) galat: 3 to 3 ki powers mein aata hai.
- (d) galat: 7 bhi 3/7 ke chakra ka ank hai.
Q8. β2βΏ + 1 prime haiβ haiβ¦
Solution dekho
Sahi jawab: (b)
- (a) galat: n = 3: 9 prime nahi, to hamesha nahi.
- (b) sahi: n = 1: 3 prime, n = 3: 9 nahi β kabhi-kabhi β
- (c) galat: n = 2: 5 prime, to βkabhi nahiβ galat.
- (d) galat: n = 1, 2, 4 pe bhi prime milta hai.
Q9. 6ΒΉβ°β° ka units digit?
Solution dekho
Sahi jawab: (a)
- (a) sahi: 6 Γ 6 = 36: hamesha 6 β
- (b) galat: 6 ki koi power 0 pe khatam nahi hoti.
- (c) galat: 4 nahi aata: 6 Γ 6 = 36.
- (d) galat: 2 nahi aata: hamesha 6 rehta.
Q10. 2Β²β° aur 10βΆ mein kaun bada?
Solution dekho
Sahi jawab: (a)
- (a) sahi: 2Β²β° = 10,48,576 > 10,00,000 β
- (b) galat: 10βΆ thoda chhota hai 2Β²β° se.
- (c) galat: 1,048,576 β 1,000,000.
- (d) galat: 2ΒΉβ° β 1,024 se turant pata chalta.
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β FAQs (Bachchon Ke Asli Sawaal)
1. Same base banana kab mumkin nahi?
Jab base alag primes hon (2 aur 3). Tab same exponent try karo, ya andaaza (210 β 103).
2. Units digit chakra hamesha 4 ka hota hai?
Nahi: 2, 3, 7, 8 ka 4; 4, 9 ka 2; 0, 1, 5, 6 ka 1. Par 4 se hamesha kaam chal jaata hai.
3. Ek counter-example se daava galat kaise?
βHameshaβ ka matlab har case. Ek bhi case fail β hamesha galat. Isliye counter-example itna taakatwar hai.
4. Kya 00 = 1?
Yeh vivaadit hai; school maths mein ise βparibhaashit nahiβ maana jaata hai. Sawaal mein a β 0 likha hota hai isi liye.
5. Olympiad mein aise sawaal aate hain?
Haan, bahut! Units digit, compare powers, last two digits: sab isi soch se.
6. Last do ank kaise nikaalein?
Wahi idea: sirf aakhri do ank pe guna karte jao, aur chakra dhundho. Jaise 74 = 2401 β last do ank 01, to har 4th power …01!
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ποΈ Practice Zone (12 Sawaal)
Q1. Easy Kaun bada: 212 ya 45?
Solution dekho
45 = 210 β 212 bada. Check: 4,096 > 1,024 β
Q2. Easy 417 ka units digit?
Solution dekho
Chakra 4, 6; 17 odd β 4. Check: 43 = 64 β
Q3. Easy 5-ank ke PIN kitne?
Solution dekho
105 = 1,00,000. WHY: har ank ke 10 choice, guna.
Q4. Easy βKisi bhi power of 10 ka units digit 0β (exponent β₯ 1)?
Solution dekho
Hamesha. WHY: 10 se guna karne pe aakhri ank 0.
Q5. Medium Kaun bada: 330 ya 520?
Solution dekho
2710 vs 2510 β 330 bada. Check: 27 > 25 β
Q6. Medium 825 ka units digit?
Solution dekho
Chakra 8, 4, 2, 6; 25 = 24 + 1 β 8. Check: 85 = 32,768 β
Q7. Medium βa2 ka units digit 2, 3, 7 ya 8 ho sakta hai?β
Solution dekho
Kabhi nahi. Squares ke units: 0, 1, 4, 5, 6, 9. Check: 0β9 ke squares gino β
Q8. Medium 2 letter (AβZ) + 3 ank wale codes kitne?
Solution dekho
262 Γ 103 = 676 Γ 1,000 = 6,76,000. Check: 26 Γ 26 = 676 β
Q9. NCERT style Kaun bada: 250, 330, 520?
Solution dekho
HCF 10 se same exponent: (25)10 = 3210, (33)10 = 2710, (52)10 = 2510 β 250 > 330 > 520. Check: 32 > 27 > 25 β
Q10. NCERT style 72026 ka units digit?
Solution dekho
2026 = 4 Γ 506 + 2 β 2nd position β 9. Check: 72 = 49 β
Q11. NCERT style 210 + 310 ka units digit?
Solution dekho
210: 10 = 8 + 2 β 4. 310 β 9. 4 + 9 = 13 β 3. Check: 1,024 + 59,049 = 60,073 β
Q12. NCERT style β2n > n2β β hamesha, kabhi-kabhi, kabhi nahi? (n = 1, 2, 3β¦)
Solution dekho
n = 1: 2 > 1 β ; n = 2: 4 = 4 β; n = 3: 8 < 9 β; n = 5: 32 > 25 β β kabhi-kabhi (n = 1 aur n β₯ 5). WHY: lambi race mein exponential jeetta (Post 7 β Linear Vs Exponential Growth).
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π§ HOTS (Sochne Wale Sawaal)
Q1. Kaun bada: 168 ya 811?
Solution dekho
232 vs 233 β 811 bada (do guna). Check: 33 β 32 = 1 β 2 guna β
Q2. 32026 β 1 ka units digit?
Solution dekho
2026 shesh 2 β 9. 9 β 1 = 8. WHY: chakra 3, 9, 7, 1.
Q3. Kya kisi bhi n ke liye 4n ka units digit 0 ho sakta hai?
Solution dekho
Nahi. 0 ke liye 2 aur 5 dono factor chahiye, 4n mein 5 kabhi nahi (prime factorisation, Post 2 β Exponent Aur Base Kya Hain?).
Q4. Kitne 4-ank ke PIN mein kam se kam ek 7 hai?
Solution dekho
Complement: kul 104 β bina 7 wale 94 = 10,000 β 6,561 = 3,439. WHY: βkam se kam ekβ = sab β koi nahi.
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π Olympiad Corner
Q1. 2100 ke kitne ank (digits) honge? (210 β 1,024)
Solution dekho
2100 = (1,024)10 β 1.27 Γ 1030 β 31 ank.
Q2. 11 + 22 + 33 + 44 + 55 ka units digit?
Solution dekho
1 + 4 + 7 + 6 + 5 = 23 β 3.
Q3. Kaun bada: 9920 ya 999910?
Solution dekho
9920 = 9,80110 < 9,99910 β 999910 bada.
Q4. 1717 ka units digit?
Solution dekho
7 ka chakra; 17 = 16 + 1 β 7.
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π CharuMam Motivation
Golu ne sirf ek taakat dekhi, Meenu ne ek cheez barabar karke dono dekhi. Yahi βtrickyβ sawaal ko aasaan banaata hai. π§
Poora Power Play chapter khatam! Aapne exponential growth se lekar arab second tak sab samjha. Ab koi bhi badi power aapko daraa nahi sakti! π
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π’ Master Recap
- π‘ Chaabi: Powers ke tricky sawaal mein pehle same base ya same exponent banao. Jab ek cheez barabar ho, to doosri dekh ke faisla turant. Exponent ke niyam isi ke auzaar hain.
- Compare: same base ya same exponent banao.
- Base > 1: bada exponent = bada number; base < 1: ulta.
- Units digit ka chakra: shesh = position, shesh 0 = aakhri.
- βHameshaβ ke liye wajah, βkabhi nahi/kabhi-kabhiβ ke liye counter-example.
- Codes: har jagah ke choices ka guna.
- βKam se kam ekβ = kul β koi nahi.
- 230 < 320: Meenu jeeti!
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π Aage Kya?
Chapter 2 poora! Ab chalte hain numbers ki kahani mein: insaan ne ginti kaise shuru ki, Roman numerals, alag-alag base aur zero ka jaadu. Chapter 3: A Story of Numbers ka hub dekhiye. π
Koi doubt? CharuMam AI Tutor se poochho, ya comment mein likho! π¬
