In this article, we would learn a simple technique of multiplying two 2-digit numbers and two 3-digit numbers in a much faster way.
1. Multiplying two 2-digit numbers:
Let the 2 numbers be AB and CD.
Their product would be calculated as follows:
AB
CD
Step 1: BD (Write only the unit’s digit and carry the rest to the next step)
Step 2: AD + BC + carry over (Cross multiply and add, write a single digit and carry rest to next step)
Step 3: AC + carry over (Write the complete number as this is the final step)
Example:
35
62
Step 1: 2×5 = 10 (Write 0 and 1 is carried forward to the next step)
Step 2: 2×3 + 6×5 + 1(from carry over) = 37 (Write 7 and 3 is carried over to next step)
Step 3: 6×3 + 3 (from carry over) = 21 (Write 21 as this is the final step)
Thus, the answer is 2170.
2. Multiplying two 3-digit numbers:
Let the 2 numbers be ABC and DEF.
Their product would be calculated as follows:
ABC
DEF
Step 1: CF (Write only the unit’s digit and carry the rest to the next step)
Step 2: BF + CE + carried over (Write only the unit’s digit and carry the rest to the next step)
Step 3: AF + CD + BE + carried over (Write only the unit’s digit and carry the rest to the next step)
Step 4: AE + BD + carried over (Write only the unit’s digit and carry the rest to the next step)
Step 5: AD + carried over (Write the complete number as this is the last step)
Example:
267
376
Step 1: 6×7 = 42 (Write 2 and 4 is carry 4 to next step)
Step 2: 6×6 + 7×7 + 4 = 89 (Write 9 and carry 8 to next step)
Step 3: 6×2 + 3×7 + 6×7 + 8 = 83 (Write 3 and carry 8 to next step)
Step 4: 3×6 + 7×2 + 8 = 40 (Write 0 and carry 4 to next step)
Step 5: 3×2 + 4 = 10 (Write 10 as this is the final step)
Thus the answer is 100392.
This way you can save time in actual exam and become more efficient.