In order to expand sales, increase profits, and reduce inventory, the mall decided to take appropriate price reduction measures. During the trial period, it was found that when the price of each commodity decreased by 1 yuan, the mall could sell 2 more per day. According to this rule, if the mall wants to make a profit of 1200 yuan per day, how much should the price of each commodity be reduced ？

Let's reduce the price of each commodity by X Yuan & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; from the meaning of the question: (40-x) (20 + 2x) = 1200 collated: x2-30x + 200 = 0 solved & nbsp; X1 = 20 & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X 2 = 10 ∵ increase profits, reduce inventory, ∵ x = 20 answer: each commodity should be reduced by 20 yuan

9 out of 16, 7 out of 18 and 5 out of 12 scored first and then compared

81 out of 144 vs 56 out of 144 vs 60 out of 144, so the first is the largest and the second the smallest

3.75 * 4 + 3 / 7-3 + 3 / 4 * 3 + 3 / 7 simple calculation 11 + 5 / 6-2 + 1 / 4-5 + 1 / 2 division 1 + 1 / 8 simple calculation

Reduction of square of fraction M-9 / 12 + m + 3 / 2

The original formula = (M & # 178; - 9) / 12 + (M + 3) / 2 = (M + 3) / 2 [(M-3) / 6 + 1] = (M + 3) / 2 [(M-3 + 6) / 6]
＝(m+3)/2 [(m+3)/6]＝(m+3)²/12,

Simple calculation (1 / 2 + 1 / 3 +... + 1 / 2003) (1 + 1 / 2 + 1 / 3 +... + 1 / 2004) - (1 + 1 / 2 + 1 / 3 +... 1 / 2003) (1 / 2 + 1 / 3 +... + 1 / 2004)

Let 1 / 2 + 1 / 3 +... + 1 / 2003 be n and 1 / 2 + 1 / 3... + 1 / 2004 be m
There are: n (1 + m) - (1 + n) M
=n+mn-m-mn
=n-m
=-1/2004

Operation law and simple operation
Fill in the appropriate number
☆+△+○=64,〇+□+☆=67,□+☆+△=63,△+〇+□=60,
〇=（）,□（）,☆=（）,△=（）,

☆+△+○=64,〇+□+☆=67,□+☆+△=63,△+〇+□=60,
The sum of, [+ △ + Θ + □ = 254 / 3
0 = (21 2 / 3), (20 2 / 3), (24 2 / 3), (17 2 / 3) and 0 = (21 2 / 3), (20 2 / 3), (24 2 / 3), (17 2 / 3),

Calculation of 75 * 24 with simple method

75*24
=25*3*4*6
=25*4*3*6
=100*18
=1800

When x = 1, the equation 2x-y = 3 has the same solution as MX + 2Y = - 1, then M=_________ .

Take x = 1 into the first one and get y = - 1
Bring x = 1, y = - 1 into
MX + 2Y = - 1, then M = 1

What is the quotient of the product of 6 and 3 / 5 and 2 / 3 minus 2 and 3 / 5 and then divided by 3 and 3 / 5?

19/18

A cuboid wooden box with a cover, the volume is 0.576 cubic meters, its length is 12 decimeters, width is 8 decimeters, to make such a wooden box at least use wood how many square meters?

12 decimeters = 1.2 meters, 8 decimeters = 0.8 meters, 0.576 ^ (1.2 × 0.8), = 0.576 ^ 0.96, = 0.6 (meters); (1.2 × 0.8 + 1.2 × 0.6 + 0.8 × 0.6) × 2, = (0.96 + 0.72 + 0.48) × 2, = 2.16 × 2, = 4.32 (square meters); answer: the wooden box needs at least 4.32 square meters