Too amazing multiplication table, keep it for teaching children the fishing skills in the stock market later.
1. Multiplication of numbers in the teens:
Mnemonic: Multiply the heads, add the tails, multiply the tails.
Example: 12×14=?
Solution: 1×1=1, 2+4=6, 2×4=8
Therefore, 12×14=168
Note: If the product of the ones place is less than two digits, use 0 as a placeholder.
2. Same head and complementary tails (the sum of the tails equals 10):
Mnemonic: Add 1 to one of the heads, then multiply the heads and multiply the tails.
Example: 23×27=?
Solution: 2+1=3, 2×3=6, 3×7=21
Therefore, 23×27=621
Note: If the product of the ones place is less than two digits, use 0 as a placeholder.
3. The first multiplier is complementary, while the second has identical digits:
Mnemonic: Add 1 to one of the heads, then multiply the heads and multiply the tails.
Example: 37×44=?
Solution: 3+1=4, 4×4=16, 7×4=28
Therefore, 37×44=1628
Note: If the product of the ones place is less than two digits, use 0 as a placeholder.
4. Multiplication of several tens by several tens:
Mnemonic: Multiply the heads, add the heads, multiply the tails, Buddhism.
Example: 21×41=?
Solution: 2×4=8, 2+4=6, 1×1=1
Therefore, 21×41=861
5. Multiplication of 11 by any number:
Mnemonic: Keep the first and last digit unchanged, sum the middle digits and drop down.
Example: 11×23125=?
Solution: 2+3=5, 3+1=4, 1+2=3, 2+5=7, with 2 and 5 at the beginning and end respectively.
Therefore, 11×23125=254375
Note: If the sum is ten or more, carry over.
6. Multiplication of numbers in the teens by any number:
Mnemonic: Keep the first digit of the second multiplicand unchanged, multiply the ones digit of the first factor by each digit of the second multiplicand, add the next digit, and then drop down.
Example: 13×326=?
Solution: The ones digit of 13 is 3, 3×3+2=11, 3×2+6=12, 3×6=18
Therefore, 13×326=4238
Note: If the sum is ten or more, carry over.
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