Multiples of 21

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Created by: Team Maths - Examples.com, Last Updated: May 23, 2024

Multiples of 21

Multiples of 21 are the numbers you get when you multiply 21 by any integer. These numbers form a sequence where each term is a product of 21 and an integer, such as 21, 42, 63, and so on. Multiples of 21 are part of basic arithmetic and play a crucial role in understanding concepts like multiplication, factors, and divisors. By identifying these multiples, students can better grasp the relationships between numbers and how they interact through multiplication. Understanding multiples also helps in solving various maths problems related to divisibility and number patterns.

What are Multiples of 21?

Multiples of 21 are numbers obtained by multiplying 21 by any integer. Examples include 21, 42, 63, 84, and so on. These multiples are integral in understanding factors, divisors, and patterns in arithmetic.

Prime factorization of 21: 21 = 3 × 7 First 10 multiples of 21: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210.

For example, 63, 105, 147 and 189 are all multiples of 21, 250 is not a multiple of 21 for the following reasons:

NumberReasonRemainder
6363 is a multiple of 21 because 21×3 = 63.0
105105 is a multiple of 21 because 21×5 = 105.0
147147 is a multiple of 21 because 21×7 = 147.0
189189 is a multiple of 21 because 21×9 = 189.0
250250 is not a multiple of 21 because 250÷21 = 11.19

List of First 100 Multiples of 21 with Remainders

List-of-First-100-Multiples-of-21
NumberReasonRemainder
2121 is a multiple of 21 because 21 × 1 = 210
4242 is a multiple of 21 because 21 × 2 = 420
6363 is a multiple of 21 because 21 × 3 = 630
8484 is a multiple of 21 because 21 × 4 = 840
105105 is a multiple of 21 because 21 × 5 = 1050
126126 is a multiple of 21 because 21 × 6 = 1260
147147 is a multiple of 21 because 21 × 7 = 1470
168168 is a multiple of 21 because 21 × 8 = 1680
189189 is a multiple of 21 because 21 × 9 = 1890
210210 is a multiple of 21 because 21 × 10 = 2100
231231 is a multiple of 21 because 21 × 11 = 2310
252252 is a multiple of 21 because 21 × 12 = 2520
273273 is a multiple of 21 because 21 × 13 = 2730
294294 is a multiple of 21 because 21 × 14 = 2940
315315 is a multiple of 21 because 21 × 15 = 3150
336336 is a multiple of 21 because 21 × 16 = 3360
357357 is a multiple of 21 because 21 × 17 = 3570
378378 is a multiple of 21 because 21 × 18 = 3780
399399 is a multiple of 21 because 21 × 19 = 3990
420420 is a multiple of 21 because 21 × 20 = 4200
441441 is a multiple of 21 because 21 × 21 = 4410
462462 is a multiple of 21 because 21 × 22 = 4620
483483 is a multiple of 21 because 21 × 23 = 4830
504504 is a multiple of 21 because 21 × 24 = 5040
525525 is a multiple of 21 because 21 × 25 = 5250
546546 is a multiple of 21 because 21 × 26 = 5460
567567 is a multiple of 21 because 21 × 27 = 5670
588588 is a multiple of 21 because 21 × 28 = 5880
609609 is a multiple of 21 because 21 × 29 = 6090
630630 is a multiple of 21 because 21 × 30 = 6300
651651 is a multiple of 21 because 21 × 31 = 6510
672672 is a multiple of 21 because 21 × 32 = 6720
693693 is a multiple of 21 because 21 × 33 = 6930
714714 is a multiple of 21 because 21 × 34 = 7140
735735 is a multiple of 21 because 21 × 35 = 7350
756756 is a multiple of 21 because 21 × 36 = 7560
777777 is a multiple of 21 because 21 × 37 = 7770
798798 is a multiple of 21 because 21 × 38 = 7980
819819 is a multiple of 21 because 21 × 39 = 8190
840840 is a multiple of 21 because 21 × 40 = 8400
861861 is a multiple of 21 because 21 × 41 = 8610
882882 is a multiple of 21 because 21 × 42 = 8820
903903 is a multiple of 21 because 21 × 43 = 9030
924924 is a multiple of 21 because 21 × 44 = 9240
945945 is a multiple of 21 because 21 × 45 = 9450
966966 is a multiple of 21 because 21 × 46 = 9660
987987 is a multiple of 21 because 21 × 47 = 9870
10081008 is a multiple of 21 because 21 × 48 = 10080
10291029 is a multiple of 21 because 21 × 49 = 10290
10501050 is a multiple of 21 because 21 × 50 = 10500
10711071 is a multiple of 21 because 21 × 51 = 10710
10921092 is a multiple of 21 because 21 × 52 = 10920
11131113 is a multiple of 21 because 21 × 53 = 11130
11341134 is a multiple of 21 because 21 × 54 = 11340
11551155 is a multiple of 21 because 21 × 55 = 11550
11761176 is a multiple of 21 because 21 × 56 = 11760
11971197 is a multiple of 21 because 21 × 57 = 11970
12181218 is a multiple of 21 because 21 × 58 = 12180
12391239 is a multiple of 21 because 21 × 59 = 12390
12601260 is a multiple of 21 because 21 × 60 = 12600
12811281 is a multiple of 21 because 21 × 61 = 12810
13021302 is a multiple of 21 because 21 × 62 = 13020
13231323 is a multiple of 21 because 21 × 63 = 13230
13441344 is a multiple of 21 because 21 × 64 = 13440
13651365 is a multiple of 21 because 21 × 65 = 13650
13861386 is a multiple of 21 because 21 × 66 = 13860
14071407 is a multiple of 21 because 21 × 67 = 14070
14281428 is a multiple of 21 because 21 × 68 = 14280
14491449 is a multiple of 21 because 21 × 69 = 14490
14701470 is a multiple of 21 because 21 × 70 = 14700
14911491 is a multiple of 21 because 21 × 71 = 14910
15121512 is a multiple of 21 because 21 × 72 = 15120
15331533 is a multiple of 21 because 21 × 73 = 15330
15541554 is a multiple of 21 because 21 × 74 = 15540
15751575 is a multiple of 21 because 21 × 75 = 15750
15961596 is a multiple of 21 because 21 × 76 = 15960
16171617 is a multiple of 21 because 21 × 77 = 16170
16381638 is a multiple of 21 because 21 × 78 = 16380
16591659 is a multiple of 21 because 21 × 79 = 16590
16801680 is a multiple of 21 because 21 × 80 = 16800
17011701 is a multiple of 21 because 21 × 81 = 17010
17221722 is a multiple of 21 because 21 × 82 = 17220
17431743 is a multiple of 21 because 21 × 83 = 17430
17641764 is a multiple of 21 because 21 × 84 = 17640
17851785 is a multiple of 21 because 21 × 85 = 17850
18061806 is a multiple of 21 because 21 × 86 = 18060
18271827 is a multiple of 21 because 21 × 87 = 18270
18481848 is a multiple of 21 because 21 × 88 = 18480
18691869 is a multiple of 21 because 21 × 89 = 18690
18901890 is a multiple of 21 because 21 × 90 = 18900
19111911 is a multiple of 21 because 21 × 91 = 19110
19321932 is a multiple of 21 because 21 × 92 = 19320
19531953 is a multiple of 21 because 21 × 93 = 19530
19741974 is a multiple of 21 because 21 × 94 = 19740
19951995 is a multiple of 21 because 21 × 95 = 19950
20162016 is a multiple of 21 because 21 × 96 = 20160
20372037 is a multiple of 21 because 21 × 97 = 20370
20582058 is a multiple of 21 because 21 × 98 = 20580
20792079 is a multiple of 21 because 21 × 99 = 20790
21002100 is a multiple of 21 because 21 × 100 = 21000

Read More About Multiples of 21

Table of 21

Important Notes

Definition: Multiples of 21 are the products of 21 and any integer. In other words, a number n is a multiple of 21 if there exists an integer k such that n = 21×kn.

Identification: To identify if a number is a multiple of 21, divide the number by 21. If the result is an integer with no remainder, the number is a multiple of 21.

First Few Multiples: The first few multiples of 21 are 21, 42, 63, 84, 105, 126, 147, 168, 189, and 210.

Properties:

  • Even Distribution: Multiples of 21 are evenly spaced by 21 units.
  • Divisibility: A multiple of 21 is always divisible by both 3 and 7, since 21 = 3×7.

Applications:

Common Multiples: Finding common multiples of 21 with other numbers can be useful in solving least common multiple (LCM) problems.

Patterns: Understanding multiples of 21 can help in recognizing numerical patterns and sequences in mathematics.

Examples: For example, 42, 84, and 126 are all multiples of 21 because 21×2 = 42, 21×4 = 84, and 21×6 = 126. Conversely, a number like 100 is not a multiple of 21 because 100÷21 does not result in an integer.

Examples on Multiples of 21

Example 1:

  • Calculation: 21×1
  • Result: 21
  • Explanation: The first multiple of 21 is 21 itself.

Example 2:

  • Calculation: 21×4
  • Result: 84
  • Explanation: Multiply 21 by 4 to get the fourth multiple of 21, which is 84.

Example 3:

  • Calculation: 21×7
  • Result: 147
  • Explanation: Multiply 21 by 7 to get the seventh multiple of 21, which is 147.

Example 4:

  • Calculation: 21×10
  • Result: 210
  • Explanation: Multiply 21 by 10 to get the tenth multiple of 21, which is 210.

Example 5:

  • Calculation: 21×12
  • Result: 252
  • Explanation: Multiply 21 by 12 to get the twelfth multiple of 21, which is 252.

Verification of Multiples

To verify if a number is a multiple of 21, divide the number by 21 and check if the remainder is zero.

Example 6:

  • Number: 189
  • Calculation: 189÷21 = 9
  • Remainder: 0
  • Explanation: Since the remainder is 0, 189 is a multiple of 21.

Example 7:

  • Number: 250
  • Calculation: 250÷21 = 11
  • Remainder: 19
  • Explanation: Since the remainder is 19, 250 is not a multiple of 21.

FAQs

What are the first five multiples of 21?

The first five multiples of 21 are 21, 42, 63, 84, and 105.

How can I determine if a number is a multiple of 21?

To determine if a number is a multiple of 21, divide the number by 21. If the quotient is an integer and the remainder is 0, the number is a multiple of 21.

Is 210 a multiple of 21?

Yes, 210 is a multiple of 21 because 210÷21 = 10, which is an integer.

What is the 10th multiple of 21?

The 10th multiple of 21 is 21×10 = 210.

Are all multiples of 21 also multiples of 7 and 3?

Yes, because 21 is 7×3, any multiple of 21 is also a multiple of both 7 and 3.

How do I find the next multiple of 21 after a given multiple?

To find the next multiple of 21, add 21 to the given multiple. For example, after 84, the next multiple is 84+21 = 105.

Is 154 a multiple of 21?

No, 154 is not a multiple of 21 because 154÷21 = 7, meaning there is a remainder of 7.

Can a negative number be a multiple of 21?

Yes, negative numbers can be multiples of 21. For example, -21, -42, and -63 are all multiples of 21.

What is the smallest multiple of 21 greater than 100?

The smallest multiple of 21 greater than 100 is 105.

How are multiples of 21 used in real life?

Multiples of 21 can be used in various contexts such as dividing groups evenly, scheduling events, or solving problems in number theory and algebra.

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