99*2008-98*2009

99*2008-98*2009

99x2008-98x2009
=(98+1)x2008-98x(2008+1)
=98x2008 + 1x2008-98x2008-98x1. The application of multiplication distribution law
=（98x2008-98x2008）+（2008-98）
=2008-98
=1910

Quarter by half

1/4X1/2
=1/8
One in eight
—+—+—+—+—+—+—+—
The total length is one, and a small section is one eighth

Read the following formula
X ^ 2 + 2x-3x = x ^ 2 + 2x + 1-4 = (x + 1) ^ 2-2 ^ 2 = (x + 1 + 2) (x + 1-2) = (x + 3) (x-1) and factorize x ^ 2-6x-1

Original formula = x ^ - 6x + 9-10
=(x-3)^2-(√10)^2
=(x-3+√10)(x-3-√10)

There are 400 science and technology books in the library, 38 less than story books. How many story books are there?

A: there are 640 story books

we put a copper wire to wind around the ciecle whose diameter is 30 cm ,just can be wound 12 rings,can you work out the length of the copper?
if the perimeter of a rectangle and a square is equal ,if the length of the square is 3.5dm,the length of rectangle is 5 dm,then how long is the width?(answer in meter)
if the perimeter of a square is7/2m,use 5/8 of its perimeter,what's the rest meter?
the perimeter of a rectangle is 24.8m,the length is 3times than the width,what's the area of a rectangle?
the perimeter of a rectangle is 24cm,draw a square on its every side,the sum of every new square is 208cm²,what's the area of the original rectangle?

1. We wrap a copper wire around a circle with a diameter of 30cm, which can be wound 12 times. Can you calculate the length of the copper wire?
30 * 12 = 360CM A: the length of copper wire is 360cm
2. If the perimeter of a rectangle and a square is equal, one side of the square is 3.5dm, and the length of the rectangle is 5DM, what is the width of the rectangle? (answer in meters)
3.5 * 2-5 = 2DM = 0.2m answer: the width of rectangle is 0.2m
3. If the perimeter of a square is 7 / 2M and 5 / 8 of its perimeter is used, how many meters are left?
7 / 2 * (1-5 / 8) = 21 / 16m A: 21 / 16m left
4. The perimeter of a rectangle is 24.8m, and its length is three times of its width. What is the area of the rectangle?
Suppose the width is XM, then the length is 3xm, (x + 3x) * 2 = 24.8, then the length is 9.3m and the width is 3.1m if x = 3.1
9.3 * 3.1 = 28.83 square meters answer: the area of rectangle is 28.83 square meters
5. The perimeter of a rectangle is 24cm, and a square is drawn on each side. The sum of the area of the new square is 208 square centimeters. What is the area of the original rectangle?
The sum of length and width of a rectangle is 12 cm. Suppose the length is x cm and the width is 12-x cm
There are four new squares, two of which are x cm long and the other two are 12-x cm long. The square of X + the square of (12-x) = 208 / 2 = 104
According to the principle that length is larger than width, the area of the original rectangle is 20 square centimeter if the length is 10 centimeter and the width is 2 centimeter

How many rivers are there in Asia over 1000 kilometers long?
Thank you!

Asia is a continent with the largest number of rivers in the world, known as the "giant River continent". There are more than 50 rivers with a length of more than 1000 km, and 5 rivers with a length of more than 4000 km. The Yangtze River is the largest in Asia, with a total length of 6300 km
The data comes from junior high school geography textbooks

Translation of unit3.section b.3a

Ben Lambert's vacation plan famous French singer Ben Lambert is going to take a long vacation this summer! He thought about going to Greece or Spain. But he finally decided to go to Canada. "I always spend my holidays in Europe," he said. "This time I want to do something different. I hear Canada is beautiful, And I know there are a lot of French speaking people there. "He was going to the Great Lakes in Canada. He was going to leave in the first week of June and stay until September. He planned to have a relaxing holiday." I'm going to walk, fish and ride a bike. I plan to spend some time in the beautiful countryside. I love nature. I hope I can forget all my troubles! At night, I rent a disc to watch, And have a good sleep. A nice holiday! I can't wait. '

The least common multiple of 1000 and 24 the least common multiple of 6,8,9,12 the least common multiple of 2,5,7,9

The least common multiple of 1000 and 24 -- 3000
6. The least common multiple of 8, 9 and 12
2. The least common multiple of 5, 7 and 9 --- 630

The two internal terms of a proportion are 8 and X, and the two external terms are 0.2 and 4 respectively. The ratio of 6 / 13 to X is equal to the ratio of 6 to 2. List the proportion and solve the problem!

1.0.2:8=x:4
0.2×4=8x
x=0.1
2.6/13:x=6:2
6/13×2=6x
x=2/13

If a, B and C are rational numbers and a / A + B / B + C / C = 1, find the value of ABC / ABC