Recurring Decimals / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ
Recurring Decimals / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ
Definition / āĻĒā§°āĻŋāĻāĻžāώāĻž
A recurring decimal is a decimal number in which one or more digits repeat forever after the decimal point. āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ āĻš’āϞ āĻāύ⧠āϏāĻāĻā§āϝāĻž āϝ’āϤ āĻĻāĻļāĻŽāĻŋāĻā§° āĻĒāĻžāĻāϤ āĻāĻāĻž āĻŦāĻž āĻāĻāĻžāϧāĻŋāĻ āϏāĻāĻā§āϝāĻž āĻ āύāύā§āϤāĻāĻžāϞāϞ⧠āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤāĻŋ āĻšāϝāĻŧāĨ¤
Major Points // āĻŽā§āĻā§āϝ āĻŦāĻŋāώā§āϏāĻŽā§āĻš
- A recurring decimal repeats a fixed pattern infinitely. āĻāĻāĻž āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ āĻ āύāύā§āϤāĻāĻžāϞāϞ⧠āĻāĻāĻž āύāĻŋā§°ā§āĻĻāĻŋāώā§āĻ āϧ⧰āĻŖ āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤāĻŋ āĻā§°ā§āĨ¤
- It is non-terminating but repeating. āĻ āĻļā§āώ āύāĻšā§ āĻāĻŋāύā§āϤ⧠āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤāĻŋāĻļā§āϞāĨ¤
- Every recurring decimal can be written as a fraction (rational number). āĻĒā§ā§°āϤāĻŋāĻā§ āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ āĻāĻā§āύāĻžāĻāĻļ (rational number) ā§°ā§āĻĒā§ āϞāĻŋāĻāĻŋāĻŦ āĻĒāĻžā§°āĻŋāĨ¤
- The repeating part is shown with a bar ( Ė ) above digits. āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻ āĻāĻļāĻā§ āϏāĻāĻā§āϝāĻžā§° āĻāĻĒā§°āϤ āĻĻāĻžāĻ ( Ė ) āĻĻāĻŋ āĻĻā§āĻā§āĻā§ąāĻž āĻšā§āĨ¤
Examples of Recurring Decimals / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻā§° āĻāĻĻāĻžāĻšā§°āĻŖ
- 0.(3) :Decimal Pattern: 3 repeats
- 0.(12): Decimal Pattern: 12 repeats
- 5.(42): Decimal Pattern: 42 repeats
Types of Decimals / āĻĻāĻļāĻŽāĻŋāĻā§° āĻĒā§ā§°āĻāĻžā§°āϏāĻŽā§āĻš
Terminating Decimal (Ends) / āĻļā§āώ āĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ āĨ¤ Ex: 0.25, 0.75, 2.4
Non-terminating Decimal (Does not end) / āĻļā§āώ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ
- Repeating / Recurring / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ: pattern repeatsāĨ¤ Ex: 0.181818…
- Non-repeating / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§: digits never repeat āĨ¤ Ex: 3.1415926…
Not Recurring Decimal / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ
Major Points / āĻŽā§āĻā§āϝ āĻŦāĻŋāώā§āϏāĻŽā§āĻš
- Digits do NOT repeat.āϏāĻāĻā§āϝāĻž āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§āĨ¤
- It can be: Terminating → ends // Non-terminating but non-repeating → goes on forever but no pattern
Examples / āĻāĻĻāĻžāĻšā§°āĻŖ:
- Terminating | āĻļā§āώ āĻšā§ā§ąāĻž: 0.5, 0.75, 3.125
- Non-terminating but non-repeating | āĻļā§āώ āύāĻšā§ āĻāĻŋāύā§āϤ⧠āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§: 0.101001000100001…, √2 = 1.414213562…
Easy Way to Remember / āϏāĻšāĻā§ āĻŽāύāϤ ā§°āĻžāĻāĻŋāĻŦāϞā§
- Recurring Decimal / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ: Digits repeat in a fixed pattern. Ex: 0.272727… (27 keeps repeating)
- Not Recurring Decimal | āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ : No digit repeats in a fixed pattern. Ex: 0.47
- Terminating Decimal | āĻļā§āώ āĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ : Stops after a limited number of digits. Ex: 1.25
- Non-terminating Decimal | āĻļā§āώ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ : Does not stop, goes on forever. Ex: 3.14…
Tricks | āĻā§ā§°āĻŋāĻāĻ
- To check if a decimal is recurring → look for repeating digits.āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ āĻāĻžāĻŦāϞ⧠→ āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āϏāĻāĻā§āϝāĻž āĻāĻžāĻāĻāĨ¤Ex: 0.727272… = recurring
- To convert recurring decimals to fractions: āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻāĻ āĻāĻā§āύāĻžāĻāĻļāϞ⧠⧰ā§āĻĒāĻžāύā§āϤ⧰ āĻā§°āĻž
- 1-digit repeating → divide by 9
- 2-digit repeating → divide by 99
- 3-digit repeating → divide by 999
- If there is a non-repeating part before repeating starts:
Assamese: āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤāĻŋ āĻā§°āĻŽā§āĻ āĻšā§ā§ąāĻžā§° āĻāĻāϤ⧠āϝāĻĻāĻŋ non-repeating āĻ āĻāĻļ āĻĨāĻžāĻā§ →
Rule | āύāĻŋāϝāĻŧāĻŽ: Numerator = (all decimal digits) – (non-recurring digits) / Denominator = 9 for each repeating + 0 for each non-repeating
Important Rule (Exam Trick) / āĻā§ā§°ā§āϤā§āĻŦāĻĒā§āϰā§āĻŖ āύāĻŋāϝāĻŧāĻŽ (āĻĒāϰā§āĻā§āώāĻž)
- A fraction is recurring if the denominator has prime factors other than 2 or 5
Ex: 1/3 → recurring (has 3), 2/7 → recurring (has 7), 5/6 → recurring (has 3)
- A fraction is NOT recurring if denominator has only 2 or 5
Ex: 1/4 → terminating (2) , 3/20 → terminating (2,5), 7/8 → terminating (2)
Summary of Decimals / āĻĻāĻļāĻŽāĻŋāĻā§° āϏāĻžāϰāĻžāĻāĻļ
Recurring Decimal / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ: Meaning / āĻ ā§°ā§āĻĨ: Repeats forever → can be written as fraction. Ex / āĻāĻĻāĻžāĻšā§°āĻŖ: 1/3, 2/7
Not Recurring Decimal / āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ : Meaning / āĻ ā§°ā§āĻĨ: No repeating pattern → terminating / irrational. Ex / āĻāĻĻāĻžāĻšā§°āĻŖ: 0.47, √2
Terminating Decimal / āĻļā§āώ āĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ: Meaning / āĻ ā§°ā§āĻĨ: Stops after a finite number of digits. Ex / āĻāĻĻāĻžāĻšā§°āĻŖ: 1.25
Non-terminating Repeating Decimal | āĻļā§āώ āύāĻšā§ā§ąāĻž āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āĻĻāĻļāĻŽāĻŋāĻ : Meaning / āĻ ā§°ā§āĻĨ: Decimal never ends, pattern repeats → recurring. Ex / āĻāĻĻāĻžāĻšā§°āĻŖ: 0.272727……
Non-terminating Non-repeating Decimal | āĻļā§āώ āύāĻšā§ā§ąāĻž āĻĒā§āύ⧰āĻžāĻŦā§āϤā§āϤ āύāĻšā§ā§ąāĻž āĻĻāĻļāĻŽāĻŋāĻ
Meaning / āĻ ā§°ā§āĻĨ: Decimal never ends, digits never repeat → irrational. Ex / āĻāĻĻāĻžāĻšā§°āĻŖ: √2, π
Recurring Decimals to Fractions : Solution : View Paper
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