The methods of calculating shadow area in fifth grade mathematics include transformation method, sum and difference method, overlapping and complementary method (including and excluding principle), complementary method, splicing method (cutting and complementing method), special position method, algebra method and symmetrical complementary method.

1, conversion method

This method transforms irregular graphics into regular graphics with equal area through equal product transformation, translation, rotation and cutting, and then calculates the area of irregular graphics by using the area formula of regular graphics.

2. Sum-difference method

Some graphics have complicated structures. Through observation, we analyze which regular patterns constitute the area of irregular patterns, and then use the sum or difference of these regular patterns to find them, thus simplifying the complex.

3. Overlapping residual method (including and excluding principle)

It is a method that transforms the area problem of the shadow part into the overlapping part of the regular figure with area, and then uses the "incompatibility principle" (sa∪b = sa+s b-sa∪b) to solve it. The shadow of this kind of problem is generally composed of several figures superimposed. It is necessary to accurately identify its structure and straighten out the size relationship between graphics.

4. Form filling method

Fill the irregular figure into a special figure, and use the area of the special figure to find the area of the original irregular figure.

5. Splicing method (cutting and repairing method)

This method is to disassemble the irregular figure, reassemble it into a new figure according to the specific situation and the needs of calculation, and try to find out the area of this new figure.

6. Special positioning method

This method is to cut a part of the graph and move it to an appropriate position in parallel, so that it can be combined into a new basic regular graph, which is convenient for calculating the area.

7. algebraic method

Graphics are classified by shape and size, and the area assumption is unknown. By establishing equations or equations, the shadow area can be solved.

8. Symmetric complementary method

This method is to make the original figure into a symmetrical figure, so as to get a new basic regular figure. The area of the original graph is half that of the new graph. It should be noted that when solving the area problem of shadow graphics, specific problems need to be analyzed in detail, so as to choose a reasonable and simple method.