Mathematics review materials for 7th grade Beijing Normal University .

Beijing Normal University Edition 7th grade mathematics courseware

1. Teaching Objectives

1.Understand and master the formulas of zero exponential power and negative exponential power, and be able to use them for proficient calculations.

2.Cultivate students' abstract mathematical thinking skills.

3.Through example problems and exercises, students will be trained in comprehensive problem-solving and calculation skills.

4.The mathematical thinking viewpoint of dialectical unity of self-application and reverse application of osmotic formulas.

Second, the key points and difficulties

1.Focus. Understand and apply the nature of exponential powers of negative integers.

2.Nodus. Understand and apply the nature and function of negative integer exponential powers, and use scientific notation to express numbers with absolute values less than 1.

3. Teaching process

1.Create a situation, review and import.

l) What is the arithmetic nature of power? Please express it in a formula.

2) Expressed in scientific notation: 69600 -5746

3) Calculation: 2The guidance is in-depth and reveals the law.

This is what we prescribe.

Rule 1: Any number that is not equal to 0 to the power of 0 is equal to 1

Sweeping with the power of the same base, if the exponent being divided is less than the exponent of the divider, for example:

It can be calculated by following the division property of the power of the same base.

This is what we prescribe.

Generally we prescribe.

Rule 2: The -p (p is a positive integer) power of any number that is not equal to 0 is equal to the reciprocal of the p-power of the number.

3.Try feedback. Understand the new knowledge.

Example 1 Calculation:

Solution: (1) Original formula.

2) Original form. 3) Original formula.

4) Original form. Example 2 The following numbers are represented by decimals:

Solution: Exercise: p 141 1, 2

Example 3 Write , as a power of 10.

The student inducts that the number of digits of an integer greater than 1 minus 1 is equal to the exponent of the power of 10. A pure decimal less than 1, the absolute value of an exponent whose number of consecutive zeros (including 0 before the decimal point) is equal to a power of 10.

Q: Write it as a product of a number with only one integer digit and a power of 10.

Solution: Like above, we can also express numbers with absolute values less than 1 in scientific notation.

Example 4 Use scientific notation to represent the following numbers:

Solution: Example 5 The mass of the earth is approximately.

tons, Jupiter's mass is about 318 times the mass of the Earth, how many tons is Jupiter's mass? (Keep 2 significant digits) Solution: (Tons) Answer: The mass of Jupiter is about tons.

Exercise: p142 1, 2

4. Summarize and expand

1.Properties of exponential powers of negative integers:

2.Expressing the law of numbers in scientific notation:

1) A number with a larger absolute value.

n is a non-negative integer, n = the integer part of the original number minus 1

2) Numbers with smaller absolute values.

n is a negative integer, the number of all zeros before the first non-zero number in the original number. (including zeros before the decimal point).

5. Assign homework

P143 Group A 4,5,6; Group B 1, 2, 3, 4