Finding several mixed operations of rational numbers Rational number + method, - method, × method are good... Also a few rational number application problems, mixed calculation problems. Oral calculation is also OK There is also the △ method... The answer with an answer can be a number, which does not need mixed calculation ....

Finding several mixed operations of rational numbers Rational number + method, - method, × method are good... Also a few rational number application problems, mixed calculation problems. Oral calculation is also OK There is also the △ method... The answer with an answer can be a number, which does not need mixed calculation ....

1. Calculation: (10 ′× 5 = 50 ′)
（1）3．28-4．76+1 - ；
（2）2．75-2 -3 +1 ；
（3）42÷（-1 ）-1 ÷（-0.125）;
（4）(-48) ÷82-(-25) ÷(-6)2;
（5）- +( )×(-2.4).
2. Calculation: (10 ′× 5 = 50 ′)
（1）-23÷1 ×（-1 ）2÷（1 ）2；
（2）-14-（2-0.5）× ×[( )2-( )3];
（3）-1 ×[1-3×(- )2]-( )2×(-2)3÷(- )3
（4）(0.12+0.32) ÷ [-22+(-3)2-3 × ];
(5)-6.24×32+31.2×(-2)3+(-0.51) ×624.
After a pile of 40 ton sand is transported once by four 5.5-ton trucks, the rest is transported by 6-ton trucks. How many times do you need to transport
mathematical problem
This is very simple
（40-4*5.5）/6=3
It will take three times
It is known that four empty bottles of mineral water can be exchanged for one bottle of mineral water. At present, there are 18 empty bottles of mineral water. If you don't pay, how much mineral water can you drink at most?
Let's change x bottles of mineral water at most. The equation is: 18 + x = 4x. The solution is x = 6. A: you can drink 6 bottles of mineral water at most
Urgent 70 rational number of mixed operations!
There should be an answer process and an answer
It's urgent
OK, we need to add
[-|98|+76+(-87)]*23[56+(-75)-(7)]-(8+4+3) 5+21*8/2-6-59 68/21-8-11*8+61 -2/9-7/9-56 4.6-(-3/4+1.6-4-3/4) 1/2+3+5/6-7/12 [2/3-4-1/4*(-0.4)]/1/3+2 22+(-4)+(-2)+4*3 -2*8-8*1/2+8/1/8 (2/3+1/2)/(-1/12)*(-1...
The diameter of the bottom surface of a cone-shaped sand pile is 6 meters and the height is 2 meters. If the sand weight per cubic meter is 1.8 tons, how many times can it be transported by an 8-ton truck?
Weight = 3.14 × (6 ／ 2) &# 178; × 2 ／ 3 × 1.8 = 33.912 tons;
Times = 33.912 △ 8 = 4.239;
So it takes 5 times;
If you don't understand this question, you can ask,
If four bottles of mineral water can be exchanged for one bottle of mineral water, how much mineral water can you drink without paying?
Four bottles, I know, but what I want to discuss is:
If he comes up and drinks another bottle, he will be able to drink up to four bottles, and finally there are three empty bottles
If he comes up for three bottles, and then goes to replace them with the ones he drinks, he drinks four bottles, but there are two empty bottles
If he borrows one bottle first, and then drinks that bottle, he will drink four bottles of water, but there is no empty bottle
Why?
Four bottles of mineral water can be exchanged for one bottle of mineral water (including one empty bottle and the water in the bottle). Note: four empty bottles = one empty bottle + the water in the bottle = three empty bottles 15 bottles of mineral water empty bottles = 15 / 3 = five bottles of water. If you don't pay, you can drink five bottles of mineral water at most. What you said is wrong, and "if he comes up, he can drink four bottles of mineral water."
How can you calculate again? If you borrow one bottle first, drink four bottles, return one bottle, and there are three empty bottles after drinking
No matter how you change it, it's 5 bottles. There are 3 bottles left. Borrow one and return one after drinking
After changing a bottle, there are 15-4 + 1 = 12 empty bottles... You can change three. After drinking, there are three empty bottles left. After borrowing one bottle of water, there are four empty bottles. Change one bottle of water to offset the borrowed one.... Five bottles in all
After changing three bottles, there are 15-12 + 3 = 6 empty bottles... Change another one. After drinking, there are three empty bottles. After borrowing a bottle of water, there are four empty bottles. Change a bottle of water to offset the borrowed one.... Five bottles in all
Take one bottle first, change four bottles after drinking, and then leave four empty bottles to offset the one you borrowed at the beginning... Or five bottles....
The mixed operation of rational number
(- 1) × 2 × (- 3) × 4 ×. × (- 49) × (- 2 to the 50th power) * 2 × 4 × 6 × 8. × 100
-1
There are 29.5 tons of coal in a pile. First, a 4-ton truck is used to transport the coal three times, and the rest is transported by a 2.5-ton truck. How many times do you have to transport the coal?
Seven more times
It is known that four empty bottles of mineral water can be exchanged for one bottle of mineral water. At present, there are 15 empty bottles of mineral water. If you don't pay, you can drink at most______ A bottle of mineral water
Let x bottles of mineral water be changed at most, and the equation is: 15 + x = 4x. The solution is x = 5, so the answer is: 5
The mixed operation of rational numbers
The shape of the outdoor unit of an air conditioner is a rectangle. Its length, width and height are 850mm, 320mm and 580mm respectively. There is a circular hole on the outward side. The diameter of the hole is 440mm. Except for this hole, the outer shell is wrapped. Please calculate the area of the outer shell iron sheet π and take 3
First calculate the area of the cuboid, then subtract the area of the hole
Area of cuboid = 2 * (850x320 + 850x580 + 320x580) = 1901200
Area of hole = π * (440 / 2) ^ 2 = 3 * 220 ^ 2 = 145200
Area of iron sheet = 1901200-145200 = 1756000 square mm (mm ^ 2)
Is this hard to calculate? First calculate the total surface area: length x width + length x height + width x height - π 2 (square) is not OK??
2X (850x320 + 850x580 + 320x580) - π x (440 / 2) (440 / 2) = 1756000 square mm = 175.6 square decimeter
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