How to multiply two digits by two digits quickly?

How to multiply two digits by two digits quickly? There are three vertical velocity algorithms. The first is the traditional operation method:

This vertical arrangement method will have carry. When the columns are arranged vertically, we must pay attention to the alignment of digits. Then, first multiply the number on one multiplier by another multiplier, and the last bit of the multiplier is aligned with the last bit of the multiplier. Then, another multiplier is multiplied by the number on the tenth bit of the multiplier in turn, and the last bit of the multiplier is aligned with the tenth bit of the multiplier. Finally, add the results obtained twice.

The characteristic of this vertical method is that it is easy to carry and needs to be added while riding.

The second vertical velocity algorithm is as follows:

The first step is to multiply the ten digits up and down so that the last digit of the number is aligned with the ten digits of the multiplier. Step 2: Multiply the single digits by ten digits, and then add the products. For example, in this question, 4 times 8 is 32, 5 times 7 is 35, and 32 plus 35 is 67.

Step 3, multiply the single digits so that the last digit of the number is aligned with the single digits of the multiplier. Note here that if there is a carry, write to the previous one.

Finally, add the results to get the product.

The characteristic of this method is that it can improve the operation speed after skilled use.

The algorithm of multiplying the last two digits by two digits is as follows:

Similarly, the columns are vertical. First, multiply the numbers of two multipliers so that the last number is aligned with the numbers of the multipliers.

Next, multiply the digits of the two multipliers by ten digits, which takes twice, and the last digit of the multiplier is aligned with the ten digits of the multiplier.

Step 4, multiply the ten digits of the two multipliers to get the last digit aligned with the hundredth digit of the multiplier.

Finally, the product is obtained by unified addition. The characteristic of this fast calculation method is that it does not need to carry in the operation, so it is clear at a glance and the result of the operation can be obtained faster.