Calculation of mathematical equations A factory has stored 50 tons of coal. Due to the improvement of furnace and coal-burning technology, 2 tons of coal can be saved every day, and the stored coal can be used for 20 days more than the original plan. How many tons of coal is the original plan to burn every day?

Calculation of mathematical equations A factory has stored 50 tons of coal. Due to the improvement of furnace and coal-burning technology, 2 tons of coal can be saved every day, and the stored coal can be used for 20 days more than the original plan. How many tons of coal is the original plan to burn every day?

It was originally planned to burn x tons of coal per day
[50/(x-2)]-(50/x)=20
50x-50(x-2)=20x(x-2)=20x^2-40x
100=20x^2-40x
x^2-2x-5=0
(x-1)^2=6
x1=1+√6=3.45
X2 = 1 - √ 6 ＜ 0
The original plan was to burn 3.45 tons of coal per day
My original

Written calculation exercises 200 equations

3X+189=521 4Y+119=22
3X*189=5 8Z/6=458
3X+77=59 4Y-6985=81
87X*13=5 7Z/93=41
15X+863-65X=54 58Y*55=27489
3X+5X=48 14X-8X=12 6*5+2X=44
20X-50=50 28+6X=88 32-22X=10
24-3X=3 10X*（5+1）=60 99X=100-X
X+3=18 X-6=12 56-2X=20
4y+2=6 x+32=76 3x+6=18
16+8x=40 2x-8=8 4x-3*9=29
8x-3x=105 x-6*5=42 x+5=7
2x+3=10 12x-9x=9 6x+18=48
56x-50x=30 5x=15 78-5x=28
32y-29=3 5x+5=15 89x-9=80
100-20x=20 55x-25x=60 76y-75=1
23y-23=23 4x-20=0 80y+20=100
53x-90=16 2x+9x=11 12y-12=24
80+5x=100 7x-8=6 65x+35=100
19y+y=40 25-5x=15 79y+y=80
42x+28x=140 3x-1=8 90y-90=90
80y-90=70 78y+2y=160 88-x=80
9-4x=1 20x=40 65y-30=100
51y-y=100 85y+1=-86 45x-50=40

To 50 fractions, four mixed operations (brackets, brackets must have) urgent! Urgent! Urgent!

1.3/7 × 49/9 - 4/3 2.8/9 × 15/36 + 1/27 3.12× 5/6 – 2/9 ×3 4.8× 5/4 + 1/4 5.6÷ 3/8 – 3/8 ÷6 6.4/7 × 5/9 + 3/7 × 5/9 7.5/2 -（ 3/2 + 4/5 ） 8.7/8 + （ 1/8 + 1/9 ） 9.9 × 5/6 + 5/6 10.3/4 ×...

In four operations, after removing the bracket, do you want to keep the bracket or change it into a bracket

Keep brackets, but this step can be omitted, you can go to brackets directly

What is the order of operations of the expressions with brackets?

First calculate the formula in the parentheses, open the parentheses, then calculate the formula in the parentheses, and finally calculate the outermost formula

Ask for 100 math problems in fourth grade volume I of Beijing Normal University Edition, with brackets and parentheses, no decimal point, no score,
Brackets, parentheses, no decimal point, no fraction

45+240÷12 124+78+22 100-35-25 （140-70）×54 63+84×2÷42 490÷7+24×526×6-110 345+99 （46-20）×30-9025×27×4 15×7+...

Off form calculation in the second semester of the fourth grade
It's better to do more

Out of formula calculation: 360 △ [(12 + 6) × 5]
288÷[（26－14）×8]
500×6-(50×2-80)
（105×12－635）÷25
864÷[（27－23）×12]
（45＋38－16）×24
500－（240＋38×6）
[64－（87－42）] ×15
（845－15×3）÷1612×[（49－28）÷7]
450÷[（84－48] ）÷12
（58+37）÷（64-9×5）
95÷（64-45）
178-145÷5×6+42
812-700÷（9+31×11）
85+14×（14+208÷26）
（284+16）×（512-8208÷18）
120-36×4÷18+35
（58+37）÷（64-9×5）
(6.8-6.8×0.55)÷8.5
0.12× 4.8÷0.12×4.8
（3.2×1.5+2.5）÷1.6
6-1.6÷4= 5.38+7.85-5.37=
7.2÷0.8-1.2×5= 6-1.19×3-0.43=
6.5×（4.8-1.2×4）=
5.8×（3.87-0.13）+4.2×3.74
32.52-（6+9.728÷3.2）×2.5
[（7.1-5.6）×0.9-1.15] ÷2.5
5.4÷[2.6×（3.7-2.9）+0.62]
12×6÷（12-7.2）-6
12×6÷7.2-6
0.68×1.9+0.32×1.9
（58+370）÷（64-45）
420+580-64×21÷28
（136+64）×（65-345÷23）
48.10.15-10.75×0.4-5.7
388+(5000-1000)
158+262+138
375+219+381+225
5001－247－1021－232
（181+2564）+2719
378+44+114+242+222
276+228+353+219
(375+1034)+(966+125)
(2130+783+270)+1017
99+999+9999+99999
7755－(2187+755)
2214+638+286
3065－738－1065
899+344
2357－183－317－357
2365－1086－214
497-299
2370+1995
3999+498
1883-398
12×25
75×24
138×25×4
(13×125)×(3×8)
(12+24+80)×50
704×25 25×32×125
32×(25+125) 88×125
102×76 58×98
178×101－178
84×36+64×84
75×99+2×75
83×102－83×2
98×199
123×18－123×3+85×123
50×(34×4)×3
25×（24+16）
178×99+178
79×42+79+79×57
7300÷25÷4
8100÷4÷75
16800÷120
30100÷2100
32000÷400
49700÷700
1248÷24
3150÷15
4800÷25
21500÷125
Additional questions: 2356 - (1356-721)
1235－（1780－1665）
75×27+19×2 5
31×870+13×310
4×(25×65+25×28)
（181+2564）+2719
378+44+114+242+222
276+228+353+219
(375+1034)+(966+125)
(2130+783+270)+1017
99+999+9999+99755－(2187+755)
2214+638+286 3065－738－1065
899+344
2357－183－317－357 2365－1086－214
497-299
2370+1995
3999+498
1883-398
12×25 75×24
138×25×4
(13×125)×(3×8)
(12+24+80)×50
704×25
25×32×125
32×(25+125)
88×125
102×76
58×98
178×101－178
84×36+64×84
75×99+2×75 83×102－83×2
98×199
123×18－123×3+85×123
50×(34×4)×3
25×（24+16）
178×99+178
79×42+79+79×57
7300÷25÷4
8100÷4÷75
16800÷120
30100÷2100
32000÷400
49700÷700
1248÷24
3150÷15
4800÷25
21500÷125
Additional questions:
2356－（1356－721）
1235－（1780－1665）
75×27+19×25
31×870+13×310
4×(25×65+25×28)

Simple calculation in Volume 2 of grade 4
199×199+199
Calculation by simple method

199×199+199
=199×(199+1)
=199×200
=(200-1)×200
=200×200-200
=40000-200
=39800

How to add, subtract, multiply and divide in Volume 2 of grade 4 of primary school
608x99 - how to make 608

It can be easily calculated as follows:
608 * 99 = 608 * （ 100 - 1 ）= 608 * 100 - 608 * 1 = 60800 - 608 = 60192

We need 100 simple exercises of quadratic equations and simple calculation. Thank you!

1) 66x + 17Y = 3967 25X + y = 1200 answer: x = 48 y = 47 (2) 18x + 23y = 2303 74x-y = 1998 answer: x = 27 y = 79 (3) 44x + 90Y = 7796 44x + y = 3476 answer: x = 79 y = 48 (4) 76x-66y = 4082 30x-y = 2940 answer: x = 98 y = 51 (5) 67x + 54y = 8546 71x-y = 56