Mutual help of computing power

1. I think there should be no relationship between the two. That is to say, the two should be the problems of different instries.

2. How to improve the calculation ability of junior one students<

the traditional formulation of mathematical ability includes:
logical thinking ability,
basic operation ability,
space imagination ability,
Application of mathematical knowledge,
ability to analyze and solve practical problems and establish mathematical models< According to the ecational objectives, it can be divided into four aspects:
mathematical knowledge,
citizen consciousness,
social needs and language communication< As we all know,
computational ability is one of the most important abilities in mathematics. It can be said that if a student lacks computational ability,
mathematics is doomed to die
the most wonderful solution depends on calculation< No matter in primary school or middle school or even in the future university,
the level of computational ability determines students' mathematical development< Therefore,
the computational ability of students is very important
to cultivate middle school students' computing ability,
we must do a good job in the first grade of junior high school
when a tall building rises from the ground,
if the foundation of the building is not firm, the consequences can be known as
. The first grade of junior high school is the foundation stage, because it is the foundation, so it is more important< The first is the poor operation skills of primary school mathematics,
most students have formed the habit of doing problems blindly with time and sweat,
although they have done many problems,
they don't really think about it< The second is the inaccurate grasp of the concept of rational number and the key points of
rule< In my teaching practice,
I have focused on the following four aspects:

first, pay attention to the foundation, grasp the key,

"rational number"
as the foundation of algebra,
is arranged at the beginning of junior one
the mastery of knowledge in this unit determines the development of junior high school mathematics. Here, we must do the following points:

1
, pay attention to knowledge generation, based on long-term development: after the number axis, absolute value, opposite number and other related knowledge reserve, enter the rational number addition operation,
we should pay special attention to the discussion of each algorithm,
don't joke like some teachers,
say:
announce the calculation method directly in class,
then start to consolidate the topic
we must fully understand the concept of the new curriculum standard,
thoroughly understand the spirit of the new curriculum,
pay attention to the generation and development of students' knowledge
when exploring the rules, we should set up the appropriate situation around the students,
let the students fully observe, think, classify, discuss and express, and understand the rules with heart. Only in this way can the students accurately
use the rules correctly and flexibly< Compared with primary school mathematics, only because of the introction of "negative number"
, the balance of primary school calculation is completely broken. How many students do wrong calculations because of mistakes in symbols is obvious to all. For example:

calculate the following questions:

(1) - 1 + 3

(2) - 12-2

(3) (- 3) x (- 5)

solution
:
original formula
= - 4

solution
:

original formula
= - 10


solution
:
original formula
= - 15


the above are all caused by "qualitative". Therefore, the author thinks that whether it is rational number addition, subtraction, multiplication Qualitative should be put in the first place in any
operation of division and power! It's a big mistake. Secondly, the operation specification of calculation must be
strictly required,
great attention should be paid from the beginning of calculation
in order to break this qualitative,
when I teach the addition of rational numbers,
I did not strictly follow the standard mathematical language calculation rules,
instead, according to the actual situation, I arranged the popular language which is in line with the students' mind,
rational and interesting,
for example, when two numbers with the same number are added together, they are all negative family, love each other

together. When the two numbers of different signs are added, one goes to the East and the other to the West. The one who is strong will listen to the other and fight, and his strength will be weakened. In this way, students can master it well, and
are very willing to learn. But we must let the students understand that we are all classmates, and we should love each other, be friendly and help each other

3
, pay attention to mixed operation and strengthen operation sequence: mixed operation is an advanced stage of rational number operation, so we should pay special attention to operation sequence and standardize operation procere. In order to avoid detours, teachers require students to read the questions as a whole, observe the mixed
operations, which operations, whether there are brackets, what should be calculated first, what should be calculated later, and what kind of rules should be used for calculation,
teachers' blackboard writing should be neat,
and have the correct mathematical format to demonstrate the calculation process,
students should be ecated step by step,
steadily
timely "friendly reminder" should be given to students where they often make mistakes. Of course, they can fall down first and then turn stone into gold. This kind of memory is more profound

4
, remind students to be patient, careful and take part in the calculation with a certain right attitude. The writing steps are complete, and the key steps
are not omitted, reflecting the order and thinking of calculation<

2. Integral addition and subtraction connect the preceding and the following:

after the end of the rational number unit,
entered the real algebraic stage
"letter represents number"
,
and the
"integral addition and subtraction"
in the letter represents number unit

has become the highlight of calculation
in order to improve the calculation ability of integral addition and subtraction,
we must pay attention to the whole process of teaching, have an overall design on the macro level, and strengthen the standardization of operation process on the micro level<

1
, learn to divide the whole into parts first, and then learn to divide the whole into parts: the essence of addition and subtraction of integral is to merge the same kind of items. Therefore, we must first have a clear understanding of the same
kind of items: the same kind of items must have two conditions:
(1)
contain the same letter
(2)
the index of the same letter is also
the same
these two conditions are indispensable
after correctly identifying the similar items,
through teaching exploration, let the students know that merging similar items is actually
the addition and subtraction of coefficients, while the letters and their indexes remain unchanged. There are two bottlenecks for students to learn the knowledge of removing brackets:
(1)
, symbol error
(2)
, missed multiplication<

for these two thorny problems,
abstract generalization is very important when learning to remove brackets< In practical teaching,
after summarizing the rule of removing brackets,
is condensed into "

'+'
(

) invariant sign

'-

'
(

) to change the sign
"catchy, students have great interest in
and have clear memory< When using the law of multiplication and distribution to remove brackets,
we should pay attention to multiply each item in brackets with a number,
just like
sharing moon cakes with each child in the class,
if we don't give Li Si food,
he will cry,
no one will be happy if he doesn't give it to anyone
therefore, every
child should be given moon cakes

2
, pay attention to the operating proceres, strengthen the calculation details: details determine success or failure, and the calculation problem is one vote veto: one step wrong step by step
wrong. Therefore, in teaching, it is necessary to standardize the steps of problem-solving, make clear which steps the integral addition and subtraction have, and make clear what should be
done in each step. Through examples and students' practice, the steps of integral addition and subtraction are summarized as follows:
1
remove brackets
2
marker
3
exchange
4
merge. In this way, students can operate step by step and rece the blindness of calculation, so as to improve their calculation ability

3
, point out the way to solve the problem, recognize the essence of the problem: in the integral addition and subtraction, there are many types of questions. For example,
students tend to think in a fixed way,
they replace letters with numbers and directly put them into integral expressions for calculation,
they lose their mind and ignore the complexity of algebraic expressions
the teacher must point to the right place,
let the students understand that it is the best policy to simplify the integral before substituting it into the evaluation. Another example is to interpret the problem of "the results of
...
do not contain
x
items, and seek the value of
m
". When learning
students to solve problems, they are blinded and cannot be considered comprehensively. Here, the teacher must point out:
"the result does not contain the
x
term, which means that the coefficient of the
x
term
= 0
after the simplification and combination of this algebraic formula
"in a word, the teacher should let the students think about the new problems in time, try to solve them, and then enlighten the students. No matter what kind of questions, if most of the students have deviation, as
teachers must seriously consider and summarize in time,
only in this way,
can improve the students' calculation ability of integral addition and subtraction to a new level.