Multiplication Tricks
The Easy Ones: Ones and ZerosSome times multiplication is a lot easier than addition. And here are a couple. ones and zeros.
Zeros - Anything multiplied by zero is.....Zero. 17 x 0 = 0 0 x 53 = 0 1 x 0 =0 Ones - anything multiplied by one is itself. 1 x 8 = 8 12 x 1 = 12 215 x 1 = 215 3's Multiplication trick This trick may not help you multiply 3's faster, but it can help you check your answer.
What could help you find your answer is to skip count by threes. Use this technique until you are able to memorize the answers. Below shows you a pattern that you find when multiplying by 3's. When you multiply any number by 3 the product (answer to a multiplication problem) will add up to be a multiple of 3. Example 3 x 4 = 12, well take 12 break it apart and add 1 + 2 = 3, 3 is a multiple of 3 3 x 5 = 15, well take 15 break it apart and add 1 + 5 =6, 6 is a multiple of 3 3 x 6 = 18, well take 18 break it apart and add 1 + 8 = 9, 9 is a multiple of 3 How about a larger number. 3 x 18 = 54, well take 54 break it apart and add 5 + 4 = 9, 9 is a multiple of 3 Even larger number 3 x 834 = 2,502, well take 2,502 break it apart and add 2 + 5 + 0 + 2 = 9, 9 is a multiple of 3 You may have seen a pattern. The digits in each of the products (answers to multiplication problems) add up to either a 3, 6 or 9 The 4 Times Table
If you know how to double a number, this one is easy.
4 x 3 is 3 doubled = 6, then double 6 = 12, 4x3=12 2x3=6 6+6=12 (or 2x6=12) 4x5 2x5=10 10+10=20 (or 2x10=20) 4x5=20 4x7 2x7=14 14+14=28 (or 2x14=28) 4x7=28 4x12 2x12=24 24+24=48 (or 2x24=48) 4x12=48 if you think about it 2x2=4, that is why this works. 9's Multiplication Trick
11's Multiplication TricksThere are two rules when multiplying by 11 (eleven).
The first 11 Times Rule: This is for the numbers 1-9 When multiplying any single digit number by 11 you just write that number twice. Multiply 11 by 3 to get 33, multiply 11 by 4 to get 44. Each number to 10 is just duplicated. The second 11 Times Rule: This is for any two digit number You are going to take the two digits of your number add them together, and put the sum in between the two digits you started with. For example: if you take 11 x 18. Jot down 1 and 8 with a space between it. 1 8. The sum of 1+8=9, do put the 9 in between the 1 and 8. so you get 198. 12 x 11 1 2 1+2=3 132 12 x 11=132 15 x 11 1 5 1+5=6 165 15 x 11=165 |
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