101*101+102*102+103*103+104*104+…… 200*200=?

101*101+102*102+103*103+104*104+…… 200*200=?

Observe some series of equations: 1! = 1, = 2x1, = 3x2x1, = 4x3x1 Calculation: / (n-1)! (n is positive)
(integer)

N! / (n-1)! = 1 * 2 * 3 * *n/1*2*3*…… *(n-1)=n

PEP fourth grade Chinese volume 2 exercises
Choose one of the three options below
Soft and tender
1. Into the depths of the Tianshan Mountains, the mountain gradually becomes ()
2. Into the depths of Tianshan, the shape of the mountain has gradually become ()
3. Dancing in the light of () makes you feel comfortable

1 (soft) 2 (soft) 3 (soft)

What number is multiplied by 3, plus 3 / 4 of the product, and then divided by 7, minus 1 / 3 of the quotient, minus 52, plus 8, and divided by 10 to get 2?
As above

Use the backward method to push forward from the number 2
（2*10-8+52）/（1-1/3）*7/（3+3*3/4）
=64/（2/3）*7/（21/4）
=96*7/（21/4）
=128
The number is 128

The shop brought in a batch of washing machines and sold 24 of them. The ratio of the number sold to the number left is 3:5. How many washing machines are there in total?

24 △ 3 × 5, = 8 × 5, = 40 (sets); 40 + 24 = 64 (sets); answer: there are 64 washing machines in total

Primary school grade 5 Volume 2 Beijing Normal University Edition equation calculation questions 10-20
To calculate, not to apply
The solution must be an integer or divisible number. Don't give me a circular decimal that can't be divided
If it's not good, it doesn't matter

Circular decimal can be replaced by XX. As for what XX is, please study and test yourself. That's it. If you still need Baidu: equation 0.5 + x) + x = 9.8 △ 2 2 2 (x + X + 0.5) = 9.8 25000 + x = 6x 3200 = 450 + 5x + X x-0.8x = 6 12x-8x = 4.8 7.5 * 2x = 15 1.2x = 81.6 x + 5.6 = 9.4 x-0

The solution equations are: (x + 7) △ 1 and 1 / 5 = 6.4 and x-x4 / 9 = 4.5 and 1 / 7

(x + 7) △ 1 and 1 / 5 = 6.4
(x+7)÷6/5 =64/10
x+7=64/10 * 6/5
x+7=384/50
x=192/25 -7
x=17/25
X-x4 / 9 = 4.5 △ 2 and one seventh
x-4/9*x=45/10 ÷ 15/7
(1-4/9)x=45/10 * 7/15
5/9 *x=21/10
x=21/10 * 9/5
x=189/50

Simple calculation of 102 times 100 plus 102

Original formula = 102 * 101 = 10302

Children's CD-ROM 15 yuan each, now promotion buy five get one free, to buy 36 such CD-ROM at least to spend how much?

Explain that the cost of buying six tickets is 15 * 5 = 75 yuan
So 36 pieces of money = 36 / 6 * 75 = 450 yuan

There is a TV set. It's sold for 900 yuan after 300 yuan. What's the price reduction?

Original price = 300 + 900 = 1200 yuan
Down: 300 △ 1200 = 25 ℅