Third grade score addition ability

1.

1. If you add (subtract) fractions with the same denominator and the denominator remains unchanged, that is, if you add (subtract) fractions with the same denominator and the denominator remains unchanged, you can rece the score

example:

< H2 > extended data:

the denominator of a fraction must not be 0, because the denominator is equivalent to a divisor. Otherwise, the equation doesn't hold. The molecule can be equal to 0, because the molecule is the divisor. It's equal to 0 divided by any number, no matter what the denominator is, the answer is 0

The numerator or denominator of a fraction can not appear irrational number (such as the square root of 2) after being reced, otherwise it is not a fraction

In the denominator of the simplest fraction, only two prime factors, 2 and 5, can be reced to finite decimals; If the denominator of the simplest fraction contains only prime factors other than 2 and 5, then it can be converted into pure cyclic decimal; If the denominator of the simplest fraction contains not only two prime factors 2 or 5, but also other prime factors other than 2 and 5, then it can be converted into mixed cycle decimal

2. 1. Pay attention to the training of oral arithmetic and lay a solid foundation of calculation
mental arithmetic is a basic skill that students must master, and it is one of the most basic and important skills in mathematics learning. Oral arithmetic is related to learning and mastering a series of contents, such as addition and subtraction of multiple digits, multiplication and division, and four calculation of decimal and fraction
for example, the decomposition of numbers within 10, the addition and subtraction of numbers within 20, and the multiplication and division in the table should be blurted out, which plays a key role in improving the accuracy of calculation. Only by improving the oral arithmetic skills, can students achieve correct, rapid and flexible calculation
2. Strengthen the training of estimation and develop students' thinking
estimation is the ability to approximate or roughly estimate the operation process or result. Estimation is helpful for students to find out their deviation in solving problems, to rethink and calculate, so as to improve their computing ability. In teaching, teachers should teach students some estimation methods, so that students can form a correct way of thinking and improve the accuracy of calculation
3. Strengthening "daily practice" can help students accumulate computing experience
daily oral calculation, appropriate amount of written calculation and comparative training can effectively promote students to continuously accumulate experience in calculation and form skills
effective practice is a means to improve computational ability
in order to make students master the skills of calculation and form the ability of calculation, it is necessary to strengthen the practice. The former is to help students consolidate new knowledge and form skills; The latter is to cultivate students' ability to flexibly use what they have learned to solve practical problems. Practice is not to ask students to do some repetitive and monotonous questions endlessly. In order to improve the efficiency of the exercise, the content of the exercise should be targeted, hierarchical and with a certain slope. The forms of exercises should be flexible. Interesting data and novel questions will stimulate students' interest in doing exercises. In a word, diversified exercises not only enrich the content and form of exercises, but also greatly mobilize the enthusiasm of students to participate in the exercises, and play a promoting role in improving students' computing ability.

3. First, find the least common multiple of the denominator, and then divide. Finally, the denominator remains unchanged and the numerator is added. If the numerator denominator of the final answer can be reced, it should be simplified

4.

1. The same denominator fraction addition and subtraction, denominator unchanged, that is, the fraction unit unchanged, numerator addition and subtraction, can be reced points

example:

< H2 > extended data:

the definition of score in primary school is different from that after primary school. 7 / 7 and 12 / 6 in primary school are considered as scores. But in fact, only rational numbers that are not equal to integers are fractions, so 7 / 7, 12 / 6 and so on are not fractions

divide the unit "1" into several parts averagely, and the number indicating such a part or parts is called a true fraction, such as 3 / 8 or 2 / 5, which may also become a false fraction, that is, the numerator is greater than or equal to the denominator, such as 8 / 3. The denominator means to divide an object into several parts, and the numerator means to take several parts

if the numerator is above and the denominator is below, it can also be seen as a division. Divide the numerator by the denominator (because 0 can't be a divisor in division, so the denominator can't be 0). On the contrary, division can also be expressed as a fraction

5. 1-1/1/3/3/3/3
7/8-8-1-1/8/8/8
1-3/6/6
1-3/6/6/6
9/25+25+7+7+7/25+7/25/25/25/25 /br / >25/36+36+11 11/36+11/36 /br / >29/33+33+13/33+ 13/13/13/13/66 /br / >5/9/9+9+7/9+7/7/18/18/br of 9/10 plus< br />5/9-7/18
6/5/2.4
2/[13/10]
6/9+1/9
7/9-4/9
6/9-1/4
3/6+3/7
5/8-1/2
8/9+2/3

6. Go to the bookstore and look for the papers!!