कक्षा 6–8Numberपाठ उपलब्ध
Integers
The integers ℤ = {…, −2, −1, 0, 1, 2, …} on the number line: additive inverses, the laws of arithmetic, the sign rules with a proof that (−a)(−b) = ab, and why most integers have no multiplicative inverse in ℤ.
math.number.integers
इस पर आधारित
4 अनिवार्य पूर्वापेक्षाएँ (बिल्कुल नीचे तक)
आप सीखेंगे
- Place integers on the number line and interpret negative numbers as opposites, debts, temperatures below zero or positions left of zero.
- Add, subtract and multiply integers, explaining subtraction as adding the additive inverse.
- Prove from the distributive law that a · 0 = 0, (−a)b = −(ab) and (−a)(−b) = ab.
- Explain why every integer has an additive inverse in ℤ while only 1 and −1 have multiplicative inverses in ℤ.
परिभाषा
- The integers are the whole numbers 0, 1, 2, … together with their negatives −1, −2, −3, ….
- The additive inverse (opposite) of a is the integer −a with a + (−a) = 0.
- Subtraction is defined by a − b = a + (−b).
- A multiplicative inverse of a is a number b with ab = 1.
प्रमेय
- Addition and multiplication of integers are commutative and associative, multiplication distributes over addition, 0 is the additive identity and 1 the multiplicative identity.
- Every integer has exactly one additive inverse.
- a · 0 = 0 and (−a)(−b) = ab for all integers a and b, as consequences of the distributive law.
- The only integers with a multiplicative inverse in ℤ are 1 and −1.
- ℤ has no zero divisors: if ab = 0 then a = 0 or b = 0.
आम भ्रांतियाँ
- Reading '−' only as 'negative': −a is positive when a is negative, and '−' can also mean 'subtract' or 'the opposite of'.
- Believing (−a)(−b) = ab is an arbitrary convention; it is forced by the distributive law.
- Thinking −5 > −2 because 5 > 2.
- Assuming every integer has an integer reciprocal.
आगे ले जाता है
वैकल्पिक खोजें
- Algebraic structures: monoids, groups and rings Under addition the integers have an identity (0) and every element has an inverse: they form a group. Under multiplication only 1 and −1 have inverses, so ℤ is a ring but not a field.विस्मय पथ →
- Groups (ℤ, +) is the infinite cyclic group, generated by 1.विस्मय पथ →
- Rings, ideals and fields (ℤ, +, ×) is the prototype of a commutative ring with identity; enlarging it to ℚ gives every non-zero element a multiplicative inverse.विस्मय पथ →
- Clock arithmetic: remainders and modular arithmetic On a clock, adding 12 hours changes nothing: arithmetic with remainders wraps the infinite line of integers into a finite circle.विस्मय पथ →
- Congruences a ≡ b (mod n) means that n divides a − b; congruence respects addition and multiplication.विस्मय पथ →
- Relations, equivalence relations and partitions Grouping integers by their remainder on division by n splits ℤ into n families, the classes of an equivalence relation.विस्मय पथ →
- Constructing ℤ, ℚ and ℝ The integers can be constructed from the natural numbers as equivalence classes of pairs (a, b), thought of as a − b.विस्मय पथ →
- ← Addition, subtraction and place value to 100
अधिगम पथ
आगे पढ़ने के लिए
- I. M. Gelfand and A. Shen, Algebra (1993)
- Hung-Hsi Wu, Understanding Numbers in Elementary School Mathematics (2011)