In this tutorial, we are going to learn the shortcut how to multiply any 2 digit numbers. This method of multiplication is called Criss-Cross method of multiplication.
If both the multiplicand and the multiplier is a 2-digit number, you can get the answer in 3 steps.
Let’s explain with an example. Suppose you want to multiply 32×21.
Let’s understand the steps involved.
Step 1 : Multiply the digits in the unit place, that is 2×1=2. This will be the unit digit of the answer as well.
Step 2 : Now this is important. Now, we cross-multiply the numbers 3×1=2 and 2×2=4 and add them. This is why it is referred to as the term criss-cross multiplication. Write 7 in the 10’s place of the answer.
Step 3 : This is the last step. You just multiply the digits in the 10’s place, that is 3×2=6.
So, the product will be :
The complete steps involved in the calculation can be illustrated in the following figure.
If you practice this shortcut, you can multiply the any 2 -digit numbers mentally without actually doing any computation.
Let’s take another example. Let’s consider the multiplication 47×32. The complete steps involved in the calculation is illustrated in the figure:
Notice the carry-forward in each step. It is important to note that only 1 digit should be retained in each steps. The rest is carry forward.
Important Note :
Number of steps involved in the criss-cross multiplication = 2x(number of digits) – 1
- For 2-digit multiplication, number of steps : 2×2- 1 = 3
- For 3-digit multiplication, number of steps : 2×3- 1 = 5
- For 4-digit multiplication, number of steps : 2×4- 1 = 7
Easy 🙂 ?
Exercise : On the similar lines, can you multiply,
- 18 x 19
- 72 x 43
- 92 x 99
- 56 x 65
I hope this tutorial is useful. If you have any doubts concerning this tutorial, please leave a comment, I would be glad to help.