THE OTHER SIDE OF ZERO
Chapter 10, 'The Other Side of Zero', introduces students to integers, which include positive numbers, negative numbers, and zero. It explains how to represent quantities like floors below ground, temperatures below freezing, and financial debits using negative numbers. Students learn about the concept of a 'zero pair' and how to perform basic operations like addition and subtraction with integers. Understanding integers is crucial for advanced mathematical concepts and real-world problem-solving.
Negative Numbers ka Introduction
Jab hum counting numbers (1, 2, 3...) aur zero (0) se aage badhte hain, toh humein negative numbers milte hain. Ye numbers zero se chhote hote hain.
- Natural Numbers (N): Counting numbers {1, 2, 3, ...}
- Whole Numbers (W): Natural numbers + Zero {0, 1, 2, 3, ...}
- Integers (Z): Whole numbers + Negative numbers {... -3, -2, -1, 0, 1, 2, 3 ...}
Number Line par Representation
- Number line par, zero center mein hota hai.
- Zero ke right side mein positive integers hote hain (1, 2, 3...).
- Zero ke left side mein negative integers hote hain (-1, -2, -3...).
- Jitna right mein jayenge, number utna bada hoga. Jitna left mein jayenge, number utna chhota hoga.
`mermaid graph LR subgraph Number Line A[-5] --- B[-4] --- C[-3] --- D[-2] --- E[-1] --- F[0] --- G[1] --- H[2] --- I[3] --- J[4] --- K[5] end `
Comparing Integers
- Har positive integer har negative integer se bada hota hai.
- Zero har positive integer se chhota hota hai, aur har negative integer se bada hota hai.
- Do positive integers mein, jo number zero se door hota hai, woh bada hota hai (e.g., 5 > 2).
- Do negative integers mein, jo number zero ke paas hota hai, woh bada hota hai (e.g., -2 > -5). Zero se jitna door negative number, utna chhota.
Example:
5 > -3(Positive number is always greater than negative number)0 > -7(Zero is always greater than negative number)-1 > -10(On number line, -1 is to the right of -10)
Additive Inverse
- Har integer ka ek additive inverse hota hai.
- Additive inverse woh number hota hai jise original number mein add karne par sum zero aata hai.
- Ek number
aka additive inverse-ahota hai, aur-aka additive inverseahota hai. - Example:
5ka additive inverse-5hai, kyunki5 + (-5) = 0. - Example:
-8ka additive inverse8hai, kyunki-8 + 8 = 0.
Real-life Examples
- Temperature:
+5°C(5 degrees above zero),-10°C(10 degrees below zero). - Height/Depth:
+100m(100m above sea level),-50m(50m below sea level). - Money:
+₹500(profit/credit),-₹200(loss/debit). - Building Floors:
+3(3rd floor above ground),-2(2nd basement floor).
Integers: Natural numbers, zero, aur negative numbers ke collection ko integers kehte hain. Isse Z se denote karte hain.
Zero (0) na toh positive integer hai aur na hi negative integer. Ye ek neutral integer hai.
Zero Pairs aur Token Model
Integers ke addition aur subtraction ko samajhne ke liye token model bahut helpful hai. Ismein hum positive aur negative tokens ka use karte hain.
- Positive Token:
+1ko represent karta hai (e.g., green token). - Negative Token:
-1ko represent karta hai (e.g., red token).
Zero Pair
- Ek positive token
(+1)aur ek negative token(-1)milkar ek zero pair banate hain. (+1) + (-1) = 0- Zero pair ka matlab hai ki woh ek dusre ko cancel kar dete hain, aur net result zero hota hai.
Addition of Integers using Tokens
- Same Signs (Positive + Positive):
- Example:
(+3) + (+2) - 3 positive tokens + 2 positive tokens = 5 positive tokens.
- Result:
+5
- Same Signs (Negative + Negative):
- Example:
(-3) + (-2) - 3 negative tokens + 2 negative tokens = 5 negative tokens.
- Result:
-5
- Different Signs (Positive + Negative):
- Example:
(+5) + (-2) - 5 positive tokens aur 2 negative tokens lo.
- 2 zero pairs banao (ek positive aur ek negative token).
- Zero pairs cancel ho jayenge.
- Bache hue tokens dekho (3 positive tokens).
- Result:
+3
- Example:
(+2) + (-5) - 2 positive tokens aur 5 negative tokens lo.
- 2 zero pairs banao.
- Bache hue tokens dekho (3 negative tokens).
- Result:
-3
Key Rule for Addition:
- Same Signs: Numbers ko add karo aur common sign laga do.
(+a) + (+b) = +(a+b)(-a) + (-b) = -(a+b)- Different Signs: Bade number se chhote number ko subtract karo aur bade number ka sign laga do.
(+a) + (-b)or(-a) + (+b)
Subtraction of Integers using Tokens
Subtraction ka matlab hai 'tokens ko nikalna'.
- Positive - Positive:
- Example:
(+5) - (+2) - 5 positive tokens lo. Usmein se 2 positive tokens nikal do.
- Bache hue tokens: 3 positive tokens.
- Result:
+3
- Negative - Negative:
- Example:
(-5) - (-2) - 5 negative tokens lo. Usmein se 2 negative tokens nikal do.
- Bache hue tokens: 3 negative tokens.
- Result:
-3
- When you need to remove tokens that are not there:
- Example:
(+2) - (+5) - 2 positive tokens hain. 5 positive tokens nikalne hain, jo possible nahi hai directly.
- Is case mein, zero pairs add karo jab tak required tokens available na ho jayein.
- 2 positive tokens hain. 3 zero pairs add karo (3 positive + 3 negative).
- Ab total 5 positive tokens aur 3 negative tokens hain.
- 5 positive tokens nikal do.
- Bache hue tokens: 3 negative tokens.
- Result:
-3
Subtraction as Addition of Additive Inverse:
- Subtraction ko hum hamesha addition mein convert kar sakte hain.
a - b = a + (-b)(jahan-bbka additive inverse hai).a - (-b) = a + b(jahanb-bka additive inverse hai).
Example:
(+7) - (+3) = (+7) + (-3) = +4(-8) - (-2) = (-8) + (+2) = -6(+5) - (-4) = (+5) + (+4) = +9(-6) - (+3) = (-6) + (-3) = -9
Zero Pair: +1 aur -1 ka combination jo 0 ke barabar hota hai. Ye integers ke addition aur subtraction ko visualize karne mein help karta hai.
Subtraction karte waqt, hamesha yaad rakho ki a - b ka matlab a + (-b) hota hai. Is rule ko apply karne se mistakes kam hoti hain.
Integers Real-World Contexts mein
Integers hamari daily life mein kai jagah use hote hain. Inhe samajhna bahut zaroori hai.
Common Applications:
- Temperature:
+sign: Above0°C(e.g.,+25°Cmeans 25 degrees Celsius above freezing point).-sign: Below0°C(e.g.,-5°Cmeans 5 degrees Celsius below freezing point).
- Altitude/Depth:
+sign: Above sea level (e.g.,+8848mfor Mount Everest).-sign: Below sea level (e.g.,-11000mfor Mariana Trench).
- Money/Finance:
+sign: Profit, credit, deposit, income.-sign: Loss, debit, withdrawal, expense.- Example: Bank account mein
₹500deposit kiya(+₹500),₹200nikala(-₹200).
- Sports:
- Goal difference in football (e.g.,
+3means 3 more goals scored than conceded). - Golf scores (e.g.,
-2means 2 strokes under par).
- Time:
+sign: Future (e.g.,+5days from today).-sign: Past (e.g.,-3days from today).
- Direction:
- East/North ko positive, West/South ko negative maan sakte hain.
- Up ko positive, Down ko negative.
Examples of Integer Operations in Context:
- Temperature Change: Subah temperature
5°Ctha. Shaam tak7°Cgir gaya. Ab temperature kya hai? +5 + (-7) = -2°C
- Bank Balance: Aapke account mein
₹1000the. Aapne₹300nikale, phir₹500deposit kiye. Ab kitne hain? +1000 + (-300) + (+500) = +700 + 500 = +1200
- Submarine Movement: Ek submarine sea level se
200mneeche hai(-200m). Agar woh50maur neeche jati hai, toh uski position kya hogi? (-200) + (-50) = -250m
- Building Floors: Aap 3rd floor
(+3)par ho. Aapko 2 basement floor(-2)par jana hai. Kitne floors neeche jana hoga? (-2) - (+3) = (-2) + (-3) = -5floors (5 floors neeche).
Important:
- Context ko samajhna bahut zaroori hai ki kab positive aur kab negative integer use karna hai.
- Keywords jaise 'above', 'deposit', 'profit' positive indicate karte hain, jabki 'below', 'withdrawal', 'loss' negative indicate karte hain.
Real-world problems mein integers ko use karte waqt, sabse pehle decide karo ki kis quantity ko positive aur kis quantity ko negative represent karna hai. Usually, 'increase', 'above', 'profit' positive hote hain, aur 'decrease', 'below', 'loss' negative.
Integer Operations with Grids (Explorations)
Integer grids ya magic squares integers ke properties aur operations ko explore karne ka ek fun way hain. Inmein rows, columns, aur diagonals ka sum ek specific 'border sum' ya 'magic sum' ke barabar hota hai.
Grid Example:
Consider a simple grid jahan rows aur columns ka sum ek target value ho.
| | | Sum | |---|---|-----| | 2 | -5| | | -3| 4 | | |Sum|Sum| |
Steps to Solve/Complete a Grid:
- Identify the Goal: Har row aur har column ka sum ek specific target value (border sum) hona chahiye.
- Calculate Existing Sums: Jo numbers diye gaye hain, unke sums calculate karo rows aur columns mein.
- Find Missing Numbers: Missing number ko find karne ke liye, target sum se existing numbers ke sum ko subtract karo.
Example: Complete the grid with border sum 0.
| | | | Sum | |---|---|---|-----| | 2 | -3| | 0 | | | 1 | -4| 0 | | -1| | | 0 | |Sum|Sum|Sum| 0 |
Solution Steps:
- Row 1:
2 + (-3) + x = 0 -1 + x = 0x = 1
- Row 2:
y + 1 + (-4) = 0 y - 3 = 0y = 3
- Row 3:
-1 + z + w = 0(Two unknowns, so check columns first)
- Column 1:
2 + y + (-1) = 0 2 + 3 + (-1) = 05 - 1 = 4 ≠ 0(Oops, mistake in example, let's re-evaluate with a simpler one or assume the target sum is different for each row/column initially)
Let's assume the question meant to fill the grid such that each row and column sums to a given value, or we need to find the border sum.
Example 2: Find the border sum for the given grid.
| 2 | -5 | 3 | |---|----|---| | -4| 1 | 3 | | 2 | 4 | -6|
Solution:
- Row 1 Sum:
2 + (-5) + 3 = -3 + 3 = 0 - Row 2 Sum:
-4 + 1 + 3 = -3 + 3 = 0 - Row 3 Sum:
2 + 4 + (-6) = 6 - 6 = 0
- Column 1 Sum:
2 + (-4) + 2 = -2 + 2 = 0 - Column 2 Sum:
-5 + 1 + 4 = -4 + 4 = 0 - Column 3 Sum:
3 + 3 + (-6) = 6 - 6 = 0
- Diagonal 1 Sum (Top-left to Bottom-right):
2 + 1 + (-6) = 3 - 6 = -3 - Diagonal 2 Sum (Top-right to Bottom-left):
3 + 1 + 2 = 6
Is case mein, rows aur columns ka sum 0 hai, lekin diagonals ka sum different hai. Agar sabhi (rows, columns, diagonals) ka sum same hota, toh usse Magic Square kehte hain.
Learning from Grids:
- Integers ke addition aur subtraction ki practice hoti hai.
- Problem-solving skills develop hote hain.
- Zero pairs ka concept practical tarike se apply hota hai.
Grids wale questions mein, hamesha ek row ya column se start karo jismein sirf ek missing value ho. Isse calculation easy ho jati hai.
Integers ka Aitihasik Sandarbh
Integers ka concept, especially negative numbers, mathematics mein ek lambe safar ka nateeja hai.
Prachin Kaal:
- China (2nd Century BCE): Negative numbers ka earliest known use China mein hua tha. Chinese mathematicians accounting ke liye red rods (positive) aur black rods (negative) ka use karte the. Unhone negative numbers ke saath calculations ke rules bhi develop kiye the.
- India (7th Century CE): Indian mathematicians ne negative numbers ko aur zyada systematically explore kiya.
- Brahmagupta (628 CE): Apni kitab 'Brāhma-sphuṭa-siddhānta' mein, Brahmagupta ne positive numbers ko 'dhan' (wealth) aur negative numbers ko 'rin' (debt) kaha. Unhone zero, positive aur negative numbers ke liye clear rules diye the, jismein addition, subtraction, multiplication, aur division shamil the. Brahmagupta ke rules modern integer arithmetic ke kaafi kareeb the.
Europe mein Vikas:
- Europe mein negative numbers ko accept karne mein kaafi time laga. Medieval European mathematicians inhe 'fictitious' ya 'absurd' mante the.
- 17th century tak, jab algebra aur coordinate geometry develop hue, tab negative numbers ka importance aur utility samajh mein aayi.
Significance:
- Negative numbers ke introduction ne mathematics ko complete kiya aur complex problems ko solve karna possible banaya.
- Aaj, integers science, engineering, finance, aur computer science jaise har field mein fundamental hain.
Brahmagupta ko integers ke rules (especially negative numbers ke operations) ko systematically define karne ka credit diya jata hai. Unka kaam mathematics ke itihas mein ek milestone tha.