Dongdong read a story book. On the first day, he read 1 / 12 of the whole book, which is 18 pages more. On the second day, he read 1 / 5 of the whole book, which is 5 pages less, and there are 73 pages left? We need formulas, not equations

Dongdong read a story book. On the first day, he read 1 / 12 of the whole book, which is 18 pages more. On the second day, he read 1 / 5 of the whole book, which is 5 pages less, and there are 73 pages left? We need formulas, not equations

120 pages
① Equation algorithm is: let the book have N pages, then you can list the calculation formula: n * (1 / 12) + 18 + n * (1 / 5) - 5 + 73 = n, solve N = 120
② The algorithm is: (73-5 + 18) / {1 - (1 / 12) - (1 / 5)} = 120
If you understand it, you'd better use the first method, but since you don't need equations, that's the second method,
Ask a few math problems
8 of 19 * 2 of 21 + 2 of 19 * 11 of 21
(4 / 51-4 / 71) * 3 / 17-71
(9.3 * 5 / 6-7.3) / 4 / 9
[2 - (1 and 2 / 3-1.25) / 17 / 12] * 6.8
66 * 1 / 66 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1
Don't write 1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 2 + 1 of 66 * 66
8/19×2/21+2/19×11/21=8/19×2/21+11/19×2/21=2/21×(8/19+11/19)=2/21（4/51-4/71）×17-3/71=4/51×17-4/71×17-3/71=4/3-(68/71+3/71)=4/3-1=1/3（9.3×5/6-7.3）/4/9=(2×5/6+7.3×5/6-7.3)×9/4=(10/6-7.3×...
You play a little bit disorderly, but you can still do it..
Question 1: two out of 21
Question 2: 1 / 3
Question 3: 1. 0125
Question 4: 11, 6
Question 5: 36
I copy in the book, one by one, very hard..
But still hope to help you, the process I omitted, but you should understand Oh.. ... unfold
You play a little bit disorderly, but you can still do it..
Question 1: two out of 21
Question 2: 1 / 3
Question 3: 1. 0125
Question 4: 11, 6
Question 5: 36
I copy in the book, one by one, very hard..
But still hope to help you, the process I omitted, but you should understand Oh.. Put it away
Solving mathematical series
A0 = a, an + 1 = an-n-2, find the general term formula of an
A(n+1)=An-n\2
An=A(n-1)-(n-1)/2
.
A2=A1-1/2
Add to get
A(n+1)=A1-(1+2+...+n)/2=A1-n(n+1)/4
An=A1-(n-1)n/4
A1=A0=A
An=A-(n-1)n/4
）Xiao Li read a story book. She read 24 pages on the first day and 30 pages on the second day
(1) I read 10% less on the third day than on the second day. How many pages do I read on the third day
(2) I read 27% of this book in the last two days. How many pages is this book?
1.30 * (1-10%) = 27 pages
2. (24 + 30) / 27% = 200 pages
. 30 * (1-10%) = 27 pages
2. (24 + 30) / 27% = 200 pages
A mathematical problem (simple calculation)
Please help me to solve a math problem: 80% - 5 × 20% △ 250%
80%-6×20%÷250%
=80%-100%÷250%
=80%-40%
=40%
=0.4
80%-5×20%÷250%
=0.8-5×0.2÷(5/2)
=0.8-5×0.2×(2/5)
=0.8-5×0.2×0.4
=10×0.08-5×0.08
=0.08×(10-5)
=0.08×5
=0.4
=0.8-5×0.2×0.4
=0.8-0.4
=0.4
2 / 2.5 = 0.8-1 / 2.5 = 0.8-0.4 = 0.4
A ˇ n + 1 = 2 * a ˇ n + 3, find the general term formula of the sequence {a ˇ n}?
a(n+1)=2a(n)+3,
a(n+1)+3=2[a(n)+3],
{a (n) + 3} is an equal ratio sequence with the first term of a (1) + 3 and the common ratio of 2
a(n)+3=[a(1)+3]2^(n-1),
a(n)=[a(1)+3]2^(n-1) - 3.
An = [3-A (n-1)] / 2 can be written as an-1 = (- 1 / 2) [a (n-1) - 1], that is, the sequence {an-1} is an equal ratio sequence with A1-1 as the first term and - 1 / 2 as the common ratio, so an-1 = (- 1 / 2) ^ (n-1)-
Xiao Li read a story book. She read 24 pages on the first day and 30 pages on the second day
(1) what percentage of students read less on the first day than on the second?
(2) how much more do you read the next day than the first?
(4) on the first day, I read 8 / 9 of the third day. How many pages do I read on the third day?
（30-24）÷30=6÷30=20%
（30-24）÷24=6÷24=25%
24÷8/9 =27
Xiaowen, Xiaoqiang and Xiaoye are in a race. Xiaowen is 1 / 12 faster than Xiaoqiang and Xiaoye is 1 / 12 slower than Xiaoqiang. How many times is Xiaowen faster than Xiaoye?
Let Xiaoqiang be 12, Xiaowen be 12 + 12 * 1 / 12 = 13, Xiaoye be 12 * (1-1 / 12) = 11
So Xiaowen is lobular: 13 / 11 times
A series of numbers 1,1,1,2,2,3,4,5,7,9,12,16,21 ·· is called Padova sequence
thank you
Padova sequence. 1,1,1,2,2,3,4,5,7,9,12,16,21 Such a sequence is called Padova sequence. It is very similar to fibulacci sequence, but slightly different: each number is obtained by skipping the number in front of it and adding the two numbers in front of it
Xiao Li read a story book. She read 24 pages on the first day and 30 pages on the second day. 1. After two days of reading, she still has 73% of the whole book
How many pages are left?
2. After two days of reading, the number of pages not read is 46 / 27 more than the number of pages read. How many pages are left to read?
1.(24+30) ÷(1-73%)=200
200-(24+30)=146
Answer: page 146 not read
2.（24+30）×（1+46／27）=146
A: do you have 146 pages left to read
Hello, the answer is as follows:
1. A total of 54 pages of 24 + 30 were read in two days, accounting for 27% of the whole book (1-73%)
So the whole book has 54 / 0.27 = 200 pages
So 200-54 = 146 pages left
2. Read 54 pages in two days, the number of pages not read = 54 + 54 * (46 / 27) = 54 + 92 = 146
So there are 146 pages left