Several methods need to be learned in the multiplication of Olympic numbers. In addition to addition and subtraction, multiplication and division can also use fast calculation and clever calculation to make the operation faster and more accurate.

Today, I will share some quick and clever multiplication and division skills with you.

The first method: zoom in and zoom out.

Let's look at an example first:

325÷25

=(325×4)÷(25×4)

= 1300÷ 100

= 13

In this division formula, in order to get the answer quickly, according to the law of numbers, the dividend and divisor are multiplied by 4 respectively. As we all know, dividend and divisor are expanded in the same multiple, and the quotient remains unchanged! So when both 325 and 25 are multiplied by 4, you will get two integer hundredths, which greatly simplifies the operation! Classmate, do you understand?

If we understand the method, let's do three math problems together!

The first line: 10000÷625.

In this case, you can take the same method as the above example. Divider and divisor are multiplied by 4 respectively, which becomes 40000 divided by 2500, that is, 400 divided by 25. Finally, you can get the answer 16.

The second way: 49500÷900.

Like this, you can adopt the strategy of narrowing first, that is, give the dividend and divisor, and at the same time reduce 100 times to become 495 divided by 9, so that you can easily calculate the answer with your mouth, which is 55.

The third way: 9000÷225.

Then, give the dividend and divisor, and expand or shrink the same multiple at the same time, and the quotient remains unchanged. This principle applies to this math problem. Students, how can we do quick calculation and clever calculation? You can leave this method in the comments section.

The second method: exchange combination method.

This method is actually a clever use of the commutative law and associative law of multiplication, so as to work out the answer quickly and skillfully.

Let's look at an example:

25× 125×4×8

=(25×4)×( 125×8)

= 100× 1000

= 100000

This multiplication formula, at first glance, is a multiplication of four numbers, which is more troublesome. However, if you look closely, you will find that 25 and 4 are multiplied together to get an integer, and 125 and 8 are multiplied together to get an integer, and the operation is simplified at once.

Classmate, after learning this method, the teacher will leave you a few more math problems to see if you can use this exchange and combination method flexibly and work out the answer quickly:

25× 15×8×4

25×24

25×5×64× 125

125×25×32

75× 16

125× 16

Note that some of the above formulas need to be used. Break down one of the multipliers and then multiply them!