Part I: Fractional multiplication

1, the meaning of fractional multiplication by integer: the meaning of fractional multiplication by integer is the same as that of integer multiplication, which is a simple operation to find the sum of several identical addends.

2. Calculation method of fractional multiplication by integer: the denominator remains unchanged, and the product of numerator multiplied by integer is numerator. Can be reduced to the simplest part of the quotation.

3. When calculating, you can subtract points before calculating.

4. Understand the meaning of discount. For example, a discount of 10% means that the current price is nine tenths of the original price; A 5% discount means that the current price is 95% of the original price.

5. Calculation method of fractional multiplication: numerator multiplies numerator, denominator multiplies denominator, and what can be reduced is reduced first. The calculation result needs the simplest score.

Part II: Fractional division

1, countdown. If the product of two numbers is 1, then we call one of them the reciprocal of the other. The reciprocal is the reciprocal of two numbers, and it does not exist in isolation.

2. The reciprocal of1is still1; 0 has no reciprocal. 0 has no reciprocal, because 0 cannot be the denominator of a fraction.

3. The meaning of dividing a number by a fraction is the same as integer division; Dividing a number by a fraction is equal to multiplying the reciprocal of this number.

Part III: Cuboid

1, a three-dimensional figure surrounded by six rectangles (two opposite faces are squares in special cases) is called a cuboid. An edge where two faces intersect is called an edge. The point where three sides intersect is called a vertex. The length of three sides intersecting at a vertex is called the length, width and height of a cuboid. In a cuboid, the opposite faces are exactly the same, and the opposite sides are equal in length.

2. A three-dimensional figure surrounded by six identical squares is called a cube (also called a cube). A cube has 12 sides, and all sides have the same length and the same face.

3. Cuboid and cube have the same number of faces, edges and vertices, but the edges of the cube are equal. A cube can be said to be a cuboid with equal length, width and height. It is a special cuboid.

Part IV: Mixed operation of fractions.

The order of fractional mixing operation is the same as that of integer mixing operation. Multiply first, then divide, then add and subtract, and the one in brackets counts first. The end result is the simplest score.

Verb (abbreviation of verb) Part V: Percentage

1, the meaning of percentage. Percentage refers to the percentage of one number in another. Percentage is also called percentage, percentage.

2. Method of converting decimals into percentages: To convert decimals into percentages, just move the decimal point two places to the right and add hundreds of semicolons at the back; Turn the fraction into a percentage: you can first turn the fraction into a decimal (three decimal places are usually reserved when you can't use them up), and then write it as a percentage; You can also multiply the numerator and denominator by a number at the same time to become a percentage number, and then write it as a percentage.