22 × 43 - 625 ÷ ((504 - (52 × 8 + 70) ÷ 32 + 6) ÷ 20 + 20230)
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
Bài 1: Tìm x nguyên, biết:
a) x + 5 = 20 - (12 -7)
b)15 - (3+ 2x) = 22
c) -11 - (19 - x) = 50
d)159 - (25 - x) = 43
e) (79 - x) - 43 = - (17 - 52)
f) (7 + x) - (21 - 13) = 32
g) - x + 20 = (-15) + 8 + 13
h) - (-x + 13 -142) + 18 = 55
Xin cảm ơn!
a) \(x+5=20-\left(12-7\right)\)
\(\Rightarrow x+5=20-5\)
\(\Rightarrow x+5=15\)
\(\Rightarrow x=15-5\)
\(\Rightarrow x=10\)
b) \(15-\left(3+2x\right)=2^2\)
\(\Rightarrow3+2x=15-4\)
\(\Rightarrow3+2x=11\)
\(\Rightarrow2x=11-3\)
\(\Rightarrow2x=8\)
\(\Rightarrow x=\dfrac{8}{2}\)
\(\Rightarrow x=4\)
c) \(-11-\left(19-x\right)=50\)
\(\Rightarrow19-x=-11-50\)
\(\Rightarrow19-x=-61\)
\(\Rightarrow x=61+19\)
\(\Rightarrow x=80\)
d) \(159-\left(25-x\right)=43\)
\(\Rightarrow25-x=159-43\)
\(\Rightarrow25-x=116\)
\(\Rightarrow x=25-116\)
\(\Rightarrow x=-91\)
e) \(\left(79-x\right)-43=-\left(17-52\right)\)
\(\Rightarrow\left(79-x\right)-43=52-17\)
\(\Rightarrow79-x-43=35\)
\(\Rightarrow36-x=35\)
\(\Rightarrow x=1\)
f) \(\left(7+x\right)-\left(21-13\right)=32\)
\(\Rightarrow7+x-8=32\)
\(\Rightarrow x-1=32\)
\(\Rightarrow x=32+1\)
\(\Rightarrow x=33\)
g) \(-x+20=-15+8+13\)
\(\Rightarrow-x+20=6\)
\(\Rightarrow x=20-6\)
\(\Rightarrow x=14\)
h) \(-\left(-x+13-142\right)+18=55\)
\(\Rightarrow x-13+142+18=55\)
\(\Rightarrow x+147=55\)
\(\Rightarrow x=55-147\)
\(\Rightarrow x=-92\)
c) (39 - 19) : (-2) + (34 - 22).5
d) 204:{80-[70:2-(23 +3.5)]} + 20230
Lời giải:
c. $=20:(-2)+12.5=-10+60=50$
d. $204:[80-(35-23)]+1=204:68+1=3+1=4$
c. =20:(−2)+12.5=−10+60=50=20:(−2)+12.5=−10+60=50
d. 204:[80−(35−23)]+1=204:68+1=3+1=4
Viết các phân số sau dưới dạng số thập phân
7/20 , 8/21 , 6/11 , 9/8 , 11/22 , 61/70 , 81/32 , 96/13 , 27/70 , 72/27 , 18/81 , 96/69
60-[ 36 + 43 ) : 52 ]
52023 : 5 2021 + 32 × 22 + 20240
\(=60-\dfrac{\left[36+64\right]}{25}\)
\(=60-4=56\)
\(60-[(36+4^3):5^2]\\=60-[(36+64):25]\\=60-(100:25)\\=60-4\\=56\)
60 -[ 36 + 4^3 ) :5^2
\(=60-(36+64)\div25\)
\(=60-100\div25\)
\(=60-4\)
=56
a) 72 + 20
68 – 40
350 + 30
970 – 70
b) 411 + 300
625 + 200
954 – 400
367 – 300
c) 32 + 7 + 8
54 + 7 + 3
1 + 16 + 9
96 + 40 + 4
a) 72 + 20 = 92
68 – 40 = 28
350 + 30= 380
970 – 70 = 900
b) 411 + 300 = 7811
625 + 200 = 825
954 – 400 = 554
367 – 300 =67
c) 32 + 7 + 8 = (32+8)+7=40+7=47
54 + 7 + 3 = 54 + (7+3)= 54+10=64
1 + 16 + 9 = (1+9)+16=10+16=26
96 + 40 + 4 = (96+4)+40=100+40=140
1 * 2 * 3 * 4 * 5 * 6 * 7 * 8 * 9 * 10 * 11 * 12 * 13 * 14 * 15 * 16 * 17 * 18 * 19 * 20 * 21 * 22 * 23 * 24 * 25 * 26 * 27 * 28 * 29 * 30 * 31 * 32 * 33 * 34 * 35 * 36 * 37 * 38 * 39 * 40 * 41 * 42 * 43 * 44 * 45 * 46 * 47 * 48 * 49 * 50 * 51 * 52 * 53 * 54 * 55 * 56 * 57 * 58 * 59 * 60 * 61 * 62 * 63 * 64 * 65 * 66 * 67 * 68 * 69 * 70 * 71 * 72 * 73 * 74 * 75 * 76 * 77 * 78 * 79 * 80 * 81 * 82 * 83 * 84 * 85 * 86 * 87 * 88 * 89 * 90 * 91 * 92 * 93 * 94 * 95 * 96 * 97 * 98 * 99 * 100 bằng bao nhiêu?
so sánh
\(125^{17}\) và \(625^{13}\)
\(8^{43}\) và \(28^{32}\)
12517 \(=\left(5^3\right)^{17}=5^{51}\)
\(625^{13}=\left(5^4\right)^{13}=5^{52}\)
Ta có:
551 < 552
\(\Rightarrow\) 12517 < 62513