9 () 8 () 7 () 6 () 5 () 4 () 3 () 2 () 1 () equals 10 You can only fill in + - * / in (). You can't use other budget symbols. You need it now!

9 () 8 () 7 () 6 () 5 () 4 () 3 () 2 () 1 () equals 10 You can only fill in + - * / in (). You can't use other budget symbols. You need it now!

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

Two out of three plus two out of nine times six out of seven

2/3+7/9*6/7=2/3+12/63=2/3+4/21=14/21+4/21 = 18/21=6/7

7 out of 9 plus 6 / 5 minus 3 / 2

7/9+5/6-2/3=14/18+15/18-12/18=17/18

One in two plus one in three, one in five plus nine, one in five plus seven, one in three plus one in five
Characteristic; numerator (), denominator ()
Law ()

Characteristic; numerator (all are 1), denominator (coprime)
Law (multiplication of denominators, addition of molecules)

If the electron ant P starts from point B and moves to the left at the speed of 6 unit lengths per second, and the other electron ant Q starts from point a and moves to the left at the speed of 4 unit lengths per second
Let two electronic ants meet at point D on the number axis. Do you know the number corresponding to point d? (the number corresponding to point a is - 20, and the number corresponding to point B is 100)

Let the time be t. because of the meeting, the distance difference between them in the same time is the distance between them
6t-4t=120
Then t = 60
So the distance a takes is 4T = 240
The left direction is negative, that is - 240
Then point d-240 + (- 20) = - 260

A suit of clothes is 320 yuan, and the price of trousers is 3 / 1 of that of the coat. How much are the prices of the coat and trousers?

Set clothes as X and pants as 1 / 3x
X +1/3X =320
solve equations

Root 2 + loga2 ≤ 0, find the value range of A

Root 2 + loga 2 ≤ 0
loga 2≤-√2=loga (a^-√2)
If a > 1, then 2 ≤ a ^ (- √ 2), so a ≤ (1 / 2) ^ (√ 2 / 2), due to the contradiction of (1 / 2) ^ (√ 2 / 2) 1;
If 0

1.56 L=___ Liter___ Ml & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; 3 cubic meters 40 cubic decimeters=___ Cubic meter

(1) 56 L = 1 l 560 ml; (2) 3 cubic meters 40 cubic decimeters = 3.04 cubic meters

The distance between a and B is 840 meters. The passenger and freight trains start from a and B and run in opposite directions. The passenger train runs 80 kilometers per hour and the freight train 60.5 thousand per hour
① How many kilometers do the two trains travel per hour?
② After 2 hours, two cars travel several thousand meters?
③ After 2 hours, the distance between two cars is several kilometers?
④ How many hours does it take for the two cars to meet?

① 80 + 60.5 = 140.5 (km)
② After 2 hours, two vehicles travel (80 + 60.5) × 2 = 281 (km)
③ After 2 hours, the distance between two cars is 840-281 = 559 (km)
④ Meeting time of two vehicles: 840 ÷ (80 + 60.5) = 1680 / 281 (hours)

220 g hydrochloric acid of unknown concentration (density 1.10 g / cm3) reacts completely with marble containing 50 g calcium carbonate
What is the mass fraction of solute in the solution after reaction?

Solution: CaCO3 + 2HCl = CaCl2 + CO2 + h2o100 111 4450 x y solution: x = 55.5g, y = 22G. That is to say, after the reaction, the solute is CaCl2, which is 55.5g. The mass of the solution is equal to 220g of hydrochloric acid of unknown concentration 200g + calcium carbonate 50g - overflow CO2 22G = 228g. So the solution after the reaction is dissolved in water