10 9 8 7 6 5 4 3 2 1 = 1 fill in the mathematical symbol in the brackets

10 9 8 7 6 5 4 3 2 1 = 1 fill in the mathematical symbol in the brackets

10-9-8+7+6-5-4+3+2-1

10 9 8 7 6 5 4 3 2 1 = 3 fill in the mathematical symbol in the brackets

10-9+8-7+6-5+4-3-2+1=3
Hope to be satisfied

Put the serial number of the correct answer in brackets
The bottom of a cuboid is a square with an area of 3 square meters
A.18 B.48 C.54

B
If you don't understand, ask me again, I'll be more detailed,

How to calculate the multiplication of different bases of the same index?
A * 2 + b * 2 and a * 2xb * 2

a*2Xb*2=(ab)^2

On the problem of base and index
Let's take an example: how to make it easy to add the 10th power of 4 to the 11th power of 4?
Elder brother and elder sister, help younger sister!

It will be faster
4^10 +4^11
=4^10 +4^10 ×4
=4^10（1+4）
=5×4^10

How to multiply the power of different base numbers and different exponents in mathematics, such as (6) ^ 8 * (5) ^ 9

The powers above can be separated by addition. In your example, just a few numbers are close enough to be combined
(6)^8*(5)^9 = (6)^8*(5)^(8+1) =[ (6)^8*(5)^8]*5 = (6*5)^8 *5
=30 ^ 8 * 5 can only be here in the end
If (6) ^ 8 * (5) ^ 99, it can't be simplified. You have to press the calculator

The base numbers are opposite to each other. How to multiply two numbers with different exponents,

For example, a ^ b * (- a) ^ C
=a^b*a^c*(-1)^c
=(-1)^c*a^(b+c)

Two numbers have the same index and different base. Can we multiply the base directly?

There is a cuboid 10 cm in length, 8 cm in width and 6 cm in height, from which the largest cube is cut. What is the sum of the edge lengths of the remaining parts?
A car and a truck start from city a and city B at the same time and travel in opposite directions. After the two cars meet, the car will travel 1.2 hours to city B. if the car travels 110 kilometers per hour on average and the truck 66 kilometers per hour on average, how many kilometers is the distance between City A and city B?
After cutting off four corners of a 36 square decimeter sheet of white iron, a square box without cover is made. Then the inside and outside of the box are sprayed with red paint, and the paint area and volume are calculated
A 100 meter long train passes through the track at a speed of 5 kilometers per second. It takes 20 seconds from the front of the train entering the tunnel to the rear of the train leaving the tunnel. If the time for the train to pass through the tunnel is to be reduced by 2 seconds, how many meters should the length of the train be reduced?
A passenger train and a freight train leave from station a and B at the same time. The passenger train runs 82 kilometers per hour and the freight train 68 kilometers per hour. When the two trains meet, the passenger train runs 36 kilometers more than the freight train. How many hours did the two trains run when they meet? How many kilometers is the distance between station a and station B?
A passenger car and a freight car leave from the two stations at the same time. The passenger car travels 108 kilometers per hour and the freight car 96 kilometers per hour. When the two cars meet, the passenger car travels 72 kilometers more than the freight car. How long does it take for the two trains to meet?
A passenger car and a freight car leave from the same station at the same time and run in the opposite direction. The speed of the passenger car is 1.5 times that of the freight car. After 4.5 hours, the distance between the two cars is 540 km. How many kilometers does the freight car travel per hour?

1. There is a cuboid 10 cm long, 8 cm wide and 6 cm high, from which the largest cube is cut. What is the sum of the edge lengths of the remaining parts?
Same as before. (10 + 8 + 6) × 4 = 96 (CM)
2. A car and a truck start from a and B cities at the same time and run in opposite directions. After the two cars meet, the car will travel 1.2 hours to B. if the car travels 110 kilometers per hour and the truck 66 kilometers per hour on average, how many kilometers is the distance between a and B?
(1.2 × 110 △ 66) × (110 + 66) = 352 (km)
3. Cut off four corners of a 36 square decimeter square sheet of white iron to make a square box without cover, and then spray red paint on the inside and outside of the box to calculate its paint area and volume
The key requirement is the edge length of the cube box. 36 = 6 square, 6 △ 3 = 2, and the edge length is 2 decimeters
2 × 2 × 5 × 2 = 40 (square decimeter) 2 × 2 × 2 = 8 (cubic decimeter)
4. A 100 meter long train passes through the track at the speed of 5 kilometers per second, from the front of the train into the tunnel to the rear of the train leaving the tunnel for 20 seconds. If the time of the train passing through the tunnel is to be reduced by 2 seconds, how many meters should the length of the train be reduced?
There is something wrong with this question
5. A passenger train and a freight train leave from station a and B at the same time. The passenger train runs 82 kilometers per hour and the freight train 68 kilometers per hour. When the two trains meet, the passenger train runs 36 kilometers more than the freight train. How many hours did the two trains run when they meet? How many kilometers is the distance between station a and station B?
Travel time of two trains: 36 ÷ (82-68) = 18 / 7 (hours)
Distance between station a and station B: (82 + 68) × 18 / 7 = 2700 / 7 (km)
6. A passenger car and a freight car leave from the two stations at the same time. The passenger car travels 108 kilometers per hour and the freight car 96 kilometers per hour. When the two cars meet, the passenger car travels 72 kilometers more than the freight car. How long does it take for the two trains to meet?
72 ÷ (108-96) = 6 (hours)
7. A passenger car and a freight car leave from the same station at the same time and run backward. The speed of the passenger car is 1.5 times that of the freight car. After 4.5 hours, the distance between the two cars is 540 kilometers. How many kilometers does the freight car travel per hour?
540 ﹣ 4.5 ﹣ 1 + 1.5 = 48 (km)

How to calculate the method of making up ten and breaking ten? Thank you!

When calculating, it is necessary to observe whether there are several digits of some numbers that can make up the whole ten or the whole hundred. This is called the method of making up the whole ten. When subtracting, if one digit is not enough to make up the whole ten, it is necessary to borrow one ten from the ten. This is called the method of breaking the ten
example
For example, 9 + 8 = 9 + 1 + 7 = 17, 14-9 = 10-9 + 4 = 5