# 1 grade # Introduction As a basic subject, mathematics aims to cultivate students' rational thinking and form the habit of rigorous thinking, which plays a vital role in one's future work, especially in the information age. It can be said that mathematics is closely integrated with any scientific field. The following is the relevant information, I hope it will help you.

1, positive and negative integer ten digits

2+3=5 means: 2 plus 3 equals 5, which is 5.

20+30=50 means: two tens plus three tens equals five tens, which is 50.

70-30=40 means: 7 ten MINUS 30 equals 40, which is 40.

Add and subtract ten integers, just add and subtract the tenth digit.

2, two digits plus one digit, integer ten.

(1) Do not carry it.

25+2=27 25+20=45

Count first: 5+2=7. Count first: 20+20=40.

Recalculate: 20+7=27 Recalculate: 40+5=45.

When you add two digits to one digit and integer ten digits, you should pay attention to the addition of two digits and the addition of two digits and ten digits.

The high bits of the same number can be added directly.

(2) carry

24+9=33 24+9=33

Calculate first: 4+9= 13 Calculate first: 24+6=30.

Recalculate: 20+ 13=33 Recalculate: 30+3=33.

Two digits plus one digit: the sum of digits is less than ten, and the ten digits remain unchanged;

When the numbers add up to ten, you must enter 1 to ten digits.

3, two digits MINUS one, integer ten.

(1) Don't give up

35-2=33 35-20= 15

Calculate first: 5-2=3. Let's calculate first: 30-20= 10.

Recalculate: 30+3=33 Recalculate: 10+5= 15.

When you subtract one digit from two digits, you should pay attention to the subtraction of one digit and one digit, and the subtraction of ten digits and ten digits.

The high bits of the same number can be directly subtracted.

(2) abdication

36-8=28 36-8=28

Calculate first: 10-8=2 calculate first: 16-8=8.

Recalculate: 26+2=28 Recalculate: 20+8=28.

Two digits MINUS one digit: one digit is enough, and the number on the tenth digit remains the same, which is the subtraction without abdication.

If the number of digits is not enough, 1 (make ten) from ten digits is abdication subtraction.

4, brackets

10-2-3=5 10-(2+3)=5

Calculate first: 10-2=8 Calculate first: 2+3=5.

Recalculate: 8-3=5 Recalculate: 10-5=5.

What's in brackets counts first.

5. Solve the problem of continuous addition

Three students stacked the little stars together, each with six. How many little stars did they fold together?

(1) Add solution

6+6+6= 18 (pieces)

(2) List the solutions

number of people

1

2

three

Small star number

six

12

18

6. Solve the problem of continuous decline

28 oranges, 9 in a bag. How many bags can you pack?

(1) Solve by turns.

(2) Uniform decreasing solution