Tính hợp lý
a)(100+42)x42+(200-58)x58
b)(1998:18-1443:13)x(16996-1110:30x305)
c)\(5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
1. Tính:
a) 37064 -64*(82+42966 : 217)
b) 320-(120,5 +95,25 +5,25) +84 : 12*12,5
c) \(\left(4\frac{2}{5}+2\frac{3}{7}\right)\)-\(\left(2\frac{2}{5}-5\frac{4}{7}\right)\)
d) (1998 : 18-1443 : 13) *(16996 -1110 : 30*305)
e) \(5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
g) (100+42)*42+(200-58)*58
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\(\left(a\right)37064-64\left(82+\frac{42966}{217}\right)\)
\(=37064-64\left(82+198\right)\)
\(=37064-64\cdot280\)
\(=30764-17920=19144\)
\(\left(b\right)320-\left(120,5+95,25+5,25\right)+\frac{84}{12}\cdot12,5\)
\(=320-\left(120,5+100,5\right)+7\cdot12,5\)
\(=320-221+87,5=11,5\)
\(\left(c\right)\left(4\frac{2}{5}+2\frac{3}{7}\right)-\left(2\frac{2}{5}-5\frac{4}{7}\right)\)
\(=4\frac{2}{5}-2\frac{2}{5}+2\frac{3}{7}+5\frac{4}{7}\)
\(=2+8=10\)
\(\left(d\right)\left(\frac{1998}{18}-\frac{1443}{13}\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=\left(111-111\right)\left(16996-\frac{1110}{30}\cdot305\right)\)
\(=0\left(16996-\frac{1110}{30}\cdot305\right)=0\)
\(\left(e\right)5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
\(=5\frac{3}{5}+1\frac{3}{4}+6\frac{1}{8}+4\frac{1}{4}+3\frac{7}{8}+3\frac{2}{5}\)
\(=5\frac{3}{5}+3\frac{2}{5}+1\frac{3}{4}+4\frac{1}{4}+6\frac{1}{8}+3\frac{7}{8}\)
\(=9+6+10=25\)
Tính :
A= 2016:4 + 4048:2
B = 37064-64 x (82+42966:2017)
C=(100+92 x 42) +( 200-58)x58
D= (1998:18-1443:13)x(16996-1110:30x305)
\(A=2016:4+4048:2\\ =504+2024\\ =2528\\ B=37064-64\cdot\left(82+42966:2017\right)\\ =37064-64\cdot\left(82+21,30193356\right)\\ =37064-64\cdot103,3019336\\ =37064-6611,323748\\ =30452,67625\\ C=\left(100+92\cdot42\right)+\left(200-58\right)\cdot58\\ =\left(100+3864\right)+142\cdot58\\ =3964+8236\\ =12200\\ D=\left(1998:18-1443:13\right)\cdot\left(16996-1110:30\cdot305\right)\\ =\left(111-111\right)\cdot\left(16996-1110:30\cdot305\right)\\ =0\cdot\left(16996-1110:30\cdot305\right)\\ =0\)
Tính nhanh:
a, \(\frac{131313}{151515}+\frac{131313}{353535}+\frac{131313}{636363}+\frac{131313}{999999}\)
b, \(\left(1998:18-1443:13\right)x\left(16996-1110:30x305\right)\)
c, \(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)x18\)
A) \(\frac{131313}{151515}+\frac{131313}{353535}+\frac{131313}{636363}+\frac{131313}{999999}\)
\(=\frac{10101\times13}{10101\times15}+\frac{10101\times13}{10101\times35}+\frac{10101\times13}{10101\times63}+\frac{10101\times13}{10101\times99}\)
\(=\frac{13}{15}+\frac{13}{35}+\frac{13}{63}+\frac{13}{99}\)
\(=13\times\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)
\(=13\times\frac{4}{33}=\frac{52}{33}\)
B) \(\left(1998:18-1443:13\right)\times\left(16996-1110:30\times305\right)\)
\(=\left(111-111\right)\times\left(16996-1110:30\times305\right)\)
\(=0\times\left(16996-1110:30\times305\right)\)
\(=0\)
( TẤT CẢ MỌI SỐ NHÂN VỚI 0 ĐỀU BẰNG 0)
C) \(\left(\frac{575757}{424242}+\frac{575757}{565656}+\frac{575757}{727272}\right)\times18\)
\(=\left(\frac{10101\times57}{10101\times42}+\frac{10101\times57}{10101\times56}+\frac{10101\times57}{10101\times72}\right)\times8\)
\(=\left(\frac{57}{42}+\frac{57}{56}+\frac{57}{72}\right)\times8\)
\(=\left(\frac{1}{42}+\frac{1}{56}+\frac{1}{72}\right)\times57\times8\)
\(=\frac{1}{169344}\times57\times8\)
\(=\frac{19}{7056}\)
MK KO BIẾT TÌNH NHANH ĐÂU! MK CHỈ LÀM ĐC NHƯ VẬY THÔI!!!!
CHÚC BN HỌC TỐT!!!!!!
a, = 13/15 + 13/35 + 13/63 + 13/99
= 13.( 1/15 + 1/35 + 1/63 + 1/99 )
= 13.( 1/ 3.5 + 1/5.7 + 1/7.9 + 1/ 9.11)
= 13 . ( 1/3 - 1/5 +1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11)
= 13 . ( 1/3 - 1/11)
= 13 . 3/11 = 39/11
[1998:18-1443:13]x[16996-1110:30x305]
giai ra cho mình nhé
[1998: 18 - 1443 : 13 ] nhân [16996 - 1110 ; 30 nhân 305 ] = 0
\(5\frac{3}{5}+1,75+6\frac{1}{8}+4\frac{1}{4}+3,875+3,4\)
a)\(-119\frac{3}{4}.\frac{3}{21}-\frac{13}{21}:4+\frac{6}{42}.116\frac{1}{2}\)
b)\(0,25.\left(-1199\frac{1}{2}\right)-\frac{1}{4}.\left(-2004\frac{1}{3}\right)-\frac{5}{4}\)
c)\(1\frac{3}{4}:\left(\frac{-1}{2}+\frac{2}{3}-\frac{5}{6}\right)-\left(-1,75\right)+25\%:2\)
Tính hợp lý:
a, \(\left(12-\frac{7}{18}-10\frac{13}{18}\right):x-1\frac{7}{13}=1\frac{2}{3}\)
b,\(\left[\left(6\frac{3}{7}-\frac{0,75x-2}{0,35}\right).2,8+1,75\right]:0,05=235\)
c.\(\frac{3-x}{5-x}=\left(\frac{3}{5}\right)^2\)
d,\(\left(1-\frac{3}{10}-x\right):\left(\frac{19}{10}-1-\frac{2}{5}\right)+\frac{4}{5}=1\)
e,\(\left(12\frac{7}{18}-10\frac{13}{18}\right):x-1\frac{7}{33}:\frac{8}{11}=1\frac{2}{3}\)
các bạn ơi giúp tớ với
BÀI ÔN SỐ HỌC
1. Thực hiện mỗi phép tính sau bằng 2 cách:
a)\(3\frac{4}{9}+5\frac{1}{6}\)
Ví dụ :
Cách 1: \(3\frac{4}{9}+5\frac{1}{6}=\frac{31}{9}+\frac{31}{6}=\frac{62}{18}+\frac{93}{18}=\frac{155}{18}=8\frac{11}{18}\)
Cách 2:\(3\frac{4}{9}+5\frac{1}{6}=3\frac{8}{18}+5\frac{3}{18}=8\frac{11}{18}\)
b)\(8\frac{1}{14}-6\frac{3}{7}\)
c)\(7-3\frac{6}{7}\)
2. Áp dụng tính chất phép tính & qui tắc dấu ngoặc để tính giá trị các biểu thức sau:
a)A =\(11\frac{3}{13}-\left(3\frac{4}{7}+6\frac{3}{13}\right)\)
b)B =\(\left(7\frac{4}{9}+3\frac{8}{13}\right)-5\frac{4}{3}\)
c)C =\(\frac{-2}{7}.\frac{5}{11}+\frac{-2}{7}.\frac{6}{11}+5\frac{4}{7}\)
d)D =\(0,7.1\frac{3}{5}.30.0,375.\frac{4}{7}\)
3.Tìm các số nghịch đảo của các số sau : \(\frac{4}{7};6\frac{3}{8};\frac{-3}{17};0.37\)
4.Tìm x, biết :
0,5-\(\frac{2}{3}x=\frac{5}{12}\)
Tính hợp lý nếu có thể : hỗn số
5 3/5 +1,75 +6 1/8 +4 1/4 + 3,875 -3,4
25 2/3 -(15/17+15 2/3)
5/30+15/90+25/150+35/210+45/270
hỗn số : 5 phần nguyên ; 3/5 là phân số , tương tự như vậy , giúp mình với
1, 53/51 + 1,75 + 61/8 + 41/4 + 3,875 - 3,4
53/51 + 7/4 + 61/8 + 41/4 + 31/8 - 17/5
53/51 + 7/4 + 61/8 + 31/8 + 41/4 - 17/5
53/51 + 7/4 + 23/2 + 41/4 - 17/5
53/51 + 7/4 + 41/4 + +23/2-17/5
53/51 + 12 + 41/4 + 23/2
= 7097/204