When the number of decimal places of the product is not enough, make up with 0, and then point the decimal point. If there is a zero after the decimal point, it should be removed according to the basic properties of the decimal point.
The coup of decimal multiplication is as follows:
1. To calculate the decimal multiplication, first calculate the product according to the law of integer multiplication, and then look at a factor * * *, how many decimal places there are, and count from the last digit of the product to the left and point to the decimal point. Results simplification can be simplified. Decimal multiplication estimation: first round two factors to keep integers, and then multiply them.
2. The operation order of decimal elementary arithmetic is the same as that of integer elementary arithmetic: operation at the same level, from left to right; Two-stage operation, first two and then one; Parentheses, first inside and then outside. The commutative law, associative law and distributive law of multiplication are also applicable to fractional multiplication, and the application of these algorithms can make the calculation simple.
3. The divisor of the product: Keep one decimal place, only look at a+ 1, and then get the numerical value by rounding. Reserved integer: it means accurate to one place, depending on the number on the tenth place; Keep one decimal place: it means accurate to ten places, depending on the number in the percentile; Keep two decimal places: it means accurate to one hundredth. According to the number on one thousandth, use rounding method to reserve a certain number of decimal places according to actual needs, and find the approximate value of the product.
Ways to improve math scores:
1. Do the problem independently and be diligent in thinking: Do the problem independently, without relying on others or search software. You can look through the books and find examples. Think lightly and summarize similar related problems.
2. Intensive reading of textbooks: Nowadays, many children's academic achievements are not satisfactory. A large part of the reason is that he didn't even read the textbook carefully. School teachers may also use tutoring programs in class, and then children don't preview before class, and they don't read textbooks carefully after class to digest the content.
3. Listen carefully in class: take notes after class. How important this point is, I won't say more. In order to improve classroom efficiency, we must preview carefully before class. Don't copy notes in class. If you miss the teacher's thinking and problem-solving summary, it will not be worth the candle. The notes are summarized after class.