There are 180 pages in a story book. Xiao Jun read 1 / 4 of the book on the first day and 1 / 5 of the book on the second day. How much more did he read on the second day than on the first day You must answer. I'm here. Thank you~`

There are 180 pages in a story book. Xiao Jun read 1 / 4 of the book on the first day and 1 / 5 of the book on the second day. How much more did he read on the second day than on the first day You must answer. I'm here. Thank you~`

There are 180 pages in a story book. Xiao Jun read 1 / 4 of the book on the first day and 1 / 5 of the book on the second day. How much more did he read on the second day than on the first day
1 / 4 of 180 is 180 x 1 / 4 is equal to 45. It is concluded that Xiao Jun read 45 pages on the first day and 1 / 5 of this book on the second day is 180 x 1 / 5 is equal to 36. It is concluded that Xiao Jun read 36 pages on the second day and then used 45-36 = 9 (pages)
A: I read 9 more pages the next day than the first

1. Xiaojun read a story book. On the first day, he read 1 / 8 of the whole book. On the second day, he read 9 more pages than on the first day. At this time, he saw 2 / 5 of the whole book. How many pages in total?
2. If you read a 120 page book, if you read 8 more pages, you will read 2 / 5 of the book. How much less white have you read than the pages you haven't read?

1、9÷(2/5-2x1/8)
=9÷3/20
=60 pages
2. What I saw:
120x2/5-8=40
See less than not:
(120-40-40)÷(120-40)
=40÷80
=50%

The specific algorithm of 5.5 times 17.3 plus 0.27 times 55

No equal sign
5.5×17.3+0.27×55
55×1.73+0.27×55
55×(1.73+0,27)
55×2
one hundred and ten

If x ^ 2 + y ^ 2-4x + 6y + 13 = 0, find X-Y
RT

Split 13 into 4 + 9
(x²-4x+4)+(y²+6y+9)=0
(x-2)²+(y+3)²=0
The square is greater than or equal to 0, and the sum is equal to 0
If one is greater than 0, then the other is less than 0
So both are equal to zero
So X-2 = 0, y + 3 = 0
x=2,y=-3
x-y=2-(-3)=5

If cos (Wu + a) = - 1 / 2, then sin (Wu / 2 + a)=

If cos (Wu + a) = - 1 / 2, then cosa = - 1 / 2
Sin (Wu / 2 + a) = cosa = - 1 / 2

C programming language: finding the root of quadratic equation with one variable

Simple calculation of 654321 × 9090 + 654321 × 9090 9 × 17 + 91 △ 27-5 × 17 + 79 △ 17

654321x909090 + 654321x90909 = 654321x (909090 + 90909) = 654321x99999 = 654321x (1000000-1) = 6543203456799 × 17 + 91 △ 17-5 × 17 + 45 △ 17 = (9-5) × 17 + (45 + 91) △ 17 = 4 × 17 + 136 △ 17 = 68 + 8 = 76

Find y = (e ^ x-x-1) / (x ^ 2) limit? (x tends to 0)
Such as the title

Let x = 1 / T, then t tends to zero
lim[1/t-ln(1+t)/t^2]=lim[t-ln(1+t)]/t^2
=Lim [1-1 / (1 + T)] / 2T
=lim1/2(1+t)=1/2

What can be easily calculated should be 7 out of 11 - (2 out of 3-5 out of 12)

Open the bracket, you can easily point 9 and 1 / 3

When a = 2.5, B = 1.4, find the value of 13a-3 (a + 2b)

13a-3（a+2b）＝13×2.5－3（2.5+2×1.4）＝32.5-15.9＝16.6.