Calculation (1-1 / 1949) (1-1 / 1950) (1-1 / 1951) (1 / 2011-1) (1 / 2012-1), it's better to have an explanation,

Calculation (1-1 / 1949) (1-1 / 1950) (1-1 / 1951) (1 / 2011-1) (1 / 2012-1), it's better to have an explanation,

(1 / 1 / 1949) (1 / 1 / 1950) (1 / 1 / 1951); (1 / 2011-1) (1 / 2012-1) = (- 1948 / 1949) × (- 1949 / 1950) × (- 1950 / 1951) × XX (- 2010 / 2011) × (- 2011 / 2012) a total of 64 negative numbers are multiplied, so the product is positive, and the adjacent two fractions

1949^2-1950^2+1951^2-1952^2+…… 2007 ^ 2-2008 ^ 2 + 2009 ^ 2 Calculation

Using the square difference formula 1949 ^ 2-1950 ^ 2 = (1949 + 1950) (1949-1950) = - (1949 + 1950) the same as 1951 ^ 2-1952 ^ 2 = - (1951 + 1952) the original formula = - (1949 + 1950 +...) 2008）+2009^2= -（1949+2008）x 60/2 + 2009^2= -118710+4036081= 3917371...

The difference between value and use value!

Price refers to the recognition of the exchange value of goods or services and the amount of money provided or paid by a specific buyer and seller in a transaction. Price is historical data and fact. Value reflects the quantity of goods or services available for transaction and the relationship between them and the buyer or seller. It is not historical data or fact

A three digit number, the one digit number is twice the hundred digit number, and the ten digit number is 1 larger than the hundred digit number. If the new number obtained by transposing the number of digits with the hundred digit number is larger than the original number
Two times less than nine, find the two digits
It's not for this two digit number. I just sent it wrong. It's for the original number

Is your question wrong? The correct answer is: if the new number is 49 times less than the original number by transposing the number of digits with the number of hundreds, how can you find the original number?
Let the original 100 bits be x, then the 10 bits be x + 1, and the individual bits be 2x
2【100X+10（X+1）+2X】=200X+10（X+1）+X+49
200x+20x+20+4x=200x+10x+10+x+49
13x=39
x=3
Then the hundreds are 3, the tens are 3 + 1 = 4, and the ones are 3x2 = 6. The primitive number is 346

If | A-3 | and | 2B + 6 | are opposite numbers, what is the value of 2A + B?

Two numbers greater than or equal to zero are opposite to each other only when they are both zero
All a = 3, B = - 3
2a+b=6-3=3

E is a point on the side BC of the square ABCD, AF bisects the angle DCE and intersects DC at the point F

Change to angle DAE
E is a point on the side BC of square ABCD, AF bisects ∠ DAE and intersects DC at point F
Rotate △ Abe with point a as the origin, make AB and ad coincide, e to e '
AE=AE' ,BE+DF=E'F
E'F‖AB,
∴∠AFE'=∠BAF=∠BAE+∠EAF=∠DAF+∠DAE'=∠E'AF
So AE '= e'f
Namely: AE = be + DF

99 * 99 * 99 * 99 * 99? Simple calculation
I'm thinking left, right, up and down. I can't think of it, my friends,

(100-1)^3*(100-1)^2

(): 4 = 9 of 8 = ()% = 0.75

(3) : 4 = 9 / 12 = (75)% = 0.75
Question 2: of the 7.8%, 0.87%, 86.7% and 87%, the largest is (7.8%), and the smallest is (86.7%)

A trapezoid will become a parallelogram if its upper bottom is increased by 2.5 cm; if its upper bottom is decreased by 4 cm, it will become a triangle. At this time, the area of the original trapezoid is reduced by 12 square cm______ Square centimeter

It can be seen from the meaning of the question: the upper bottom of the trapezoid is 4cm, the lower bottom is 4 + 2.5 = 6.5cm, the height is: 12 × 2 △ 4, = 24 △ 4, = 6 (CM), so the area of the trapezoid is: (4 + 6.5) × 6 △ 2, = 10.5 × 6 △ 2, = 63 △ 2, = 31.5 (cm2); answer: the area of the original trapezoid is 31.5 square centimeter, so the answer is: 31.5

Four twenty five times twenty three plus four twenty five times seventy seven

=4/25×23+4/25×77
=4/25×（23+77）
=4/25×100
=16
If my answer can solve your problem, if you have any questions, please continue to ask. Thank you for your support