Table of contents
- Multiples of 21 up to 20
- Show Me the Table for 21
- 21 Times Table: 3 Easy Tricks
- Patterns in the Multiplication Table of 21
- Solved Examples Using the Table of 21
- Common Mistakes to Watch For
- Where You Might Use the Table of 21
- How to Memorise the Table of 21
- Free Table of 21 Worksheet with Answers
- Conclusion
- Frequently Asked Questions
Ask a student which table they dread most, and 21 usually makes the list. Fair enough. The table of 21 has no neat finger trick like 9 and no easy ending like 5 or 10. The answers are big, and there are a lot of them.
But the table is more predictable than it looks. Every answer is just 21 more than the one before it, and the last digit follows a pattern you can use to check your work. In this guide you’ll find the full chart, three tricks that make the numbers easier to work out, solved examples, and a printable worksheet with answers.
Whether you’re a student preparing for a test, a parent helping with homework, or a teacher looking for classroom material, you can start with the chart below and work your way down.
Multiples of 21 up to 20
A multiple of 21 is what you get when you multiply 21 by any whole number. Here are the multiples of 21 up to 20:
Multiplication | Result |
21 × 1 | 21 |
21 × 2 | 42 |
21 × 3 | 63 |
21 × 4 | 84 |
21 × 5 | 105 |
21 × 6 | 126 |
21 × 7 | 147 |
21 × 8 | 168 |
21 × 9 | 189 |
21 × 10 | 210 |
21 × 11 | 231 |
21 × 12 | 252 |
21 × 13 | 273 |
21 × 14 | 294 |
21 × 15 | 315 |
21 × 16 | 336 |
21 × 17 | 357 |
21 × 18 | 378 |
21 × 19 | 399 |
21 × 20 | 420 |
Or in a single line: 21, 42, 63, 84, 105, 126, 147, 168, 189, 210, 231, 252, 273, 294, 315, 336, 357, 378, 399, 420.
Show Me the Table for 21
Maybe you just want the short version to read out loud. Here it is, the way most classrooms say it:
- 21 ones are 21
- 21 twos are 42
- 21 threes are 63
- 21 fours are 84
- 21 fives are 105
- 21 sixes are 126
- 21 sevens are 147
- 21 eights are 168
- 21 nines are 189
- 21 tens are 210
Read it aloud two or three times, then cover the answers and try again. Saying numbers out loud works better than most people expect, because your ear starts to recognise the rhythm.
21 Times Table: 3 Easy Tricks
Maybe you just want the short version to read out loud. Here it is, the way most classrooms say it:
- 21 ones are 21
Nobody enjoys memorising twenty big numbers in a row. These three methods let you work out the 21 times table instead of just remembering it.
Trick 1: Break 21 into 20 and 1
This is the one most students end up using for good. Multiply by 20 first, then add the number one more time.
21 × n = (20 × n) + n
- 21 × 6 = 120 + 6 = 126
- 21 × 8 = 160 + 8 = 168
- 21 × 13 = 260 + 13 = 273
Multiplying by 20 is easy: double the number, then add a zero. After that you only add the original number back.
Trick 2: Keep Adding 21
Start at 21 and keep adding 21. That’s the whole table.
21, then 42, then 63, then 84, then 105.
It’s slower, but it’s very reliable. If you forget 21 × 7, count up from 21 × 5 and you’ll land on it. It’s also a good way to check an answer you aren’t sure about.
Trick 3: Use the 3s and 7s
Since 21 is 3 × 7, you can multiply by 3 and then by 7, in either order.
Take 21 × 4. First, 4 × 3 = 12. Then 12 × 7 = 84.
This one is handy if your 3 and 7 tables are already strong.
- 21 twos are 42
- 21 threes are 63
- 21 fours are 84
- 21 fives are 105
- 21 sixes are 126
- 21 sevens are 147
- 21 eights are 168
- 21 nines are 189
- 21 tens are 210
Read it aloud two or three times, then cover the answers and try again. Saying numbers out loud works better than most people expect, because your ear starts to recognise the rhythm.
Patterns in the Multiplication Table of 21
Patterns turn a long list into something you can reason about. Here are the ones worth knowing in the multiplication table of 21.
The last digit matches the number you multiply by. 21 × 7 = 147 ends in 7. 21 × 13 = 273 ends in 3. So if you work out 21 × 9 and your answer doesn’t end in 9, you know to look again. It’s the quickest error check in the table.
Odd stays odd, even stays even. An odd multiplier gives an odd answer (21, 63, 105). An even multiplier gives an even one (42, 84, 126).
Every multiple divides by 3 and by 7. This follows directly from 21 = 3 × 7. For example, 252 ÷ 3 = 84 and 252 ÷ 7 = 36.
The digits add up to a multiple of 3. Try 63 (6 + 3 = 9), 147 (1 + 4 + 7 = 12) and 252 (2 + 5 + 2 = 9). Every time, the total divides evenly by 3.
The gap is always 21. Look down the chart and each answer is exactly 21 bigger than the one above it.
Solved Examples Using the Table of 21
Example 1: Multiplication
Find 21 × 15.
(20 × 15) + 15 = 300 + 15 = 315
Example 2: Division
Find 294 ÷ 21.
We know 21 × 14 = 294, so the answer is 14.
Example 3: Missing number
21 × ___ = 189.
From the table, 21 × 9 = 189, so the missing number is 9.
Example 4: Going past 20
Find 21 × 25.
(20 × 25) + 25 = 500 + 25 = 525
Common Mistakes to Watch For
A few slips show up again and again when students practise this table:
- Forgetting to add the extra number in Trick 1. Some students stop at 20 × 6 = 120 and forget the “+ 6”. Always finish the second step.
- Carrying errors. In 21 × 8, it’s easy to write 148 instead of 168. The last-digit check helps here, though both end in 8, so double-check the tens too.
- Mixing up neighbours. 21 × 13 and 21 × 14 are only 21 apart. If you’re unsure, add or subtract 21 from a line you know well.
Where You Might Use the Table of 21
It’s not just for exams. A few everyday examples:
- Planning ahead: 21 days is three weeks, so four lots of 21 days is 84 days.
- Packing and stock: If a box holds 21 items, 12 boxes hold 252.
- Seating: 8 rows of 21 chairs make 168 seats.
- Shopping: 7 tickets at 21 each cost 147.
How to Memorise the Table of 21
- Start small. Learn 21 × 1 to 21 × 5 first. Then add the next five.
- Practise a little every day. Five to ten minutes beats an hour the night before a test.
- Say it and write it. Using your voice and your hand gives your memory two routes to the answer.
- Self-check with the patterns. Last digit, odd or even, digit sum. These catch most mistakes.
- Cover and test. Hide the answers, fill in what you can, then check.
Free Table of 21 Worksheet with Answers
Copy this into a document and print it, or hand it out as it is.
Section A: Fill in the Blanks
- 21 × 3 = ____
- 21 × 6 = ____
- 21 × 9 = ____
- 21 × 11 = ____
- 21 × 14 = ____
- 21 × 17 = ____
- 21 × 20 = ____
- 21 × ____ = 147
- 21 × ____ = 252
- 21 × ____ = 336
Section B: Division
- 126 ÷ 21 = ____
- 210 ÷ 21 = ____
- 294 ÷ 21 = ____
- 399 ÷ 21 = ____
Section C: Mental Math
- 21 × 30 = ____
- 21 × 40 = ____
- 21 × 25 = ____
Section D: Word Problems
- A shop packs 21 pencils in each box. How many pencils are in 8 boxes?
- Meera reads 21 pages every day. How many pages does she read in 7 days?
- A hall has 12 rows with 21 chairs in each row. How many chairs are there altogether?
Answer Key
Q
Answer
Q
Answer
1
63
11
6
2
126
12
10
3
189
13
14
4
231
14
19
5
294
15
630
6
357
16
840
7
420
17
525
8
7
18
168 pencils
9
12
19
147 pages
10
16
20
252 chairs
Conclusion
The table of 21 looks like a lot to learn, but you don’t have to learn it all at once or by brute force. Pick the trick that suits you, whether that’s splitting 21 into 20 + 1, adding 21 each time, or using the 3s and 7s. Lean on the last-digit pattern to catch mistakes. Then work through the worksheet a few times over a week, and you’ll find the answers coming without much effort.
Frequently Asked Questions
252.
Split 21 into 20 + 1. Multiply by 20, then add the number once. For 21 × 9, that’s 180 + 9 = 189.
Yes. Because 21 = 3 × 7, every multiple divides evenly by both.
21, 42, 63, 84 and 105.
Want your child to build these skills with an expert mentor?