-1+-3+-5+-7+-9+、、、、+-97+-99=? By the way, 2 + - 4 + 6 + - 8 +,, + 46 + - 48 + 50

-1+-3+-5+-7+-9+、、、、+-97+-99=? By the way, 2 + - 4 + 6 + - 8 +,, + 46 + - 48 + 50

-1+-3+-5+-7+-9+、、、、+-97+-99
=-(1+3+5+7+9+、、、、+97+99)
=-[(1+99)+(3+97)+(5+95)+、、、、(49+51)]
=-(100+100+100+、、、、100)
=-2500
The other is the same algorithm. Let's do it by ourselves

Mathematics application problem, need formula
The lengths of the three sides of the triangle ABC are 4cm, 5cm and 6cm respectively. Take three points a, B and C as the center of the circle and 1cm as the radius to form an arc with the three sides of the triangle to form three small sectors (all in the interior of the triangle). Calculate the area sum of the three sectors

Because of the inner angle of the triangle and 180 degrees, the three sectors put together to form a semicircle
Therefore, according to the area formula s = π R & # 178; = 3.14 × 1 × 1 = 3.143.14 △ 2 = 1.57

What is 0.75 + (- 11 / 4) + (- 0.125) + (- 5 / 7) + (- 4 and 1 / 8)

0.75 + (- 11 / 4) + (- 0.125) + (- 5 / 7) + (- 4 and 1 / 8) = 3 / 4-11 / 4 + 1 / 8-5 / 7-33 / 8 = (3 / 4-11 / 4) + (1 / 8-33 / 8) - 5 / 7 = - 2-4-5 / 7 = - 6 and 5 / 7
Please accept if you are satisfied

Solutions of the system of equations 2x + 3Y = 15m 5x-3y = - M

Two formula addition
7x＝14m
x＝2m
y＝11/3m

Simple operation: 1998 + 199.8 + 19.98 + 1.998 + 0.1998
How should it be calculated?

1998+199.8+19.98+1.998+0.1998
=1998(1+0.1+0.01+0.001+0.0001)
=1998*1.1111
=(2000-2)*1.1111
=2222.2-2.2222
=2219.9778

If the 48th power of 2 minus 1 can be divided by two integers between 60 and 70, what are the two integers?

Factorization of square difference formula
2^48-1
=(2^24+1)(2^24-1)
=(2^24+1)(2^12+1)(2^12-1)
=(2^24+1)(2^12+1)(2^6+1)(2^6-1)
2^6+1=64+1=65
2^6-1=64-1=63
So these two integers are 65 and 63
Ask me if you have any questions

Simple calculation of 36 * 48 + 53 * 36-36

36*48+53*36-36
=36*(48+53-1)
=36*100
=3600

There is a trapezoidal part, its area is 2.52 square decimeters, its height is 0.6 decimeters, and its lower bottom is 3.6 decimeters longer than the upper bottom?

Suppose the length of the upper bottom is x, then the length of the lower bottom is (x + 3.6) M
（x+x+3.6）0.6÷2=2.52
The solution is x = 2.4
The length of the top and bottom is 2.4 decimeters
Or (2.52 × 2 ﹣ 0.6-3.6) ﹣ 2 = 2.4 (decimeter)
Are you satisfied?

There must be a process to solve equation 18 (X-2) = 9

A parallelogram and a triangle have the same base and height. The area of a known triangle is 30 square meters. Find the area of a parallelogram

30 × 2 = 60 square meters
A: the area of a parallelogram is 60 square meters