Answer: 3+ 1/5.
Solution:
(8/ 15)×( 12÷2)=3+ 1/5.
4.
The radius of the big circle is 6 cm, and the radius of the small circle is 4 cm. The difference between the shaded areas in two circles is equal to _ _ _ _ _.
Answer: 62.8.
Solution:
Yin Da 3.14× 62-x;
Silver:
3. 14×42-x
Subtraction:
3. 14×20=62.8.
5.
After a commodity has been reduced by 10% for two consecutive times, the price is 8 1 yuan. Then the original price of this item is _ _ _ _ _.
Hu Xinghu's class is at P28 1_ Question 2205.
Answer: 100 yuan.
Solution:
Let the original price be x,
Then x (1-10%) x (1-10%) = 81,
x= 100。
2. Calculation problems:
1.
The famous teacher tutored the sixth grade Zhou Xianglin to develop P25.
Answer: 1.
Solution:
1990 1990= 1990× 1000 1,
1990 1990 1990= 1990× 1000 1000 1.
1989 1989= 1989× 1000 1, 1989 1989 1989= 1989× 1000 1000 1.
So, the original formula =
== 1.
2.
Knowledge publishing house
Six P 1 1_ Example 4 of the Chinese Olympic Mathematics Textbook
Answer: 1.
Solution: Original Style =
3. Geometric problems:
1.
The figure below consists of six equal circles, and the overlapping area of every two adjacent circles is 2 square centimeters, accounting for the area of each circle. What is the total area of this figure?
Problem solving skills P367_2
Answer: 87+5/6.
Solution:
Area of each circle:
17/6÷ 1/6= 17.
17×6- 17/6×5=87+5/6.
2.
As shown in the picture, A and B are the centers of two quarter circles. So, how many square centimeters is the area difference between the two shaded parts?
Sixth grade P65_ 16 of Hangzhou Shunqing Olympic Mathematics Course
Answer: 1.42.
Solution:
1/4×3. 14×42-2×4- 1/4×3. 14×22= 1.42.
4. Answer questions:
1.
(7 points) A monkey picked a bunch of peaches, ate 1/7 peaches on the first day, ate the rest 1/6 the next day, and ate the rest 1/5, 1/4 and 65433 every day on the third, fourth and sixth days.
Hang Shunqing Olympic Mathematics Course Grade 6 P 164_ Example 5
Answer:
84.
Solution:
12÷÷÷÷÷÷
=84.
2.
(8 points) If a commodity is priced at a profit of 20% and then sold at a discount of 18%, the profit will be 16.8 yuan. What is the cost of this commodity?
Zhou Zhou exercises grade six P200_ Example 3.
Answer: 300 yuan.
Solution:
16.8÷[( 1+20%)×88%
- 1]= 16.8÷5.6%=300.
3.
(7 points)
There is a reservoir with a water inlet pipe and a water outlet pipe. It takes 5 hours to fill a pool of water and 2 hours to drain it. Now there is a pool full of water, and one person opens it in the order of drainage, water intake and drainage 1 hour.
Zhou Zhou exercises grade six P 103_ 14.
Answer: 4+4/5 hours.
Solution:
/kloc-water after 0/hour:
1- 1/2= 1/2;
There is water after 2 hours:
1/2+ 1/5=7/ 10;
There is water after 3 hours:
7/ 10- 1/2= 1/5;
There is water after 4 hours:
1/5+ 1/5=2/5.
2/5( 1/2)= 4/5 hours.
Therefore, the water is discharged after 4+4/5 hours.