a)15/6+16/5=?
b)16/8+2/5=?
c)45/9x2/3=?
1) (-5) . (-8) - 45 . (-3) +(-6) . (-12)=?
b) 6 . (-15) + (-8) . (-9) - 72 . (-2)=?
c) (-15) . 4 - (-4) .16 - (-8) . 32
1) (-5) . (-8) - 45 . (-3) +(-6) . (-12)= 247
b) 6 . (-15) + (-8) . (-9) - 72 . (-2)= 126
c) (-15) . 4 - (-4) .16 - (-8) . 32 = 260
Tính
a)1/16^7:1/8^9
b)2/3^12*2/3^13*2/3^22
c)9^16*8^11/6^33
d)4^5*2^16/16^6
e)8^10*15^16/12^15*25^8
f)2^7*9^3/6^5*8^2
i)6^15*9^10/9617*2^13
Tính nhẩm:
a)
15 − 6=..... 15 − 7=.....
15 − 8=..... 15 − 9=.....
16 − 7=..... 16 − 8=.....
16 − 9=..... 17 − 8=.....
17 − 9=..... 18 − 9=.....
b)
18 − 8 − 1=..... 18 − 9=.....
15 − 5 − 2=..... 15 − 7=.....
16 − 6 − 3=..... 16 − 9=.....
Phương pháp giải:
Trừ nhẩm các số rồi điền kết quả vào chỗ trống.
Lời giải chi tiết:
a)
15 − 6 = 9 15 − 7 = 8
15 − 8 = 7 15 − 9 = 6
16 − 7 = 9 16 − 8 = 8
16 − 9 = 7 17 − 8 = 9
17 − 9 = 8 18 − 9 = 9
b)
18 − 8 − 1 = 9 18 − 9 = 9
15 − 5 − 2 = 8 15 − 7 = 8
16 − 6 − 3 = 7 16 − 9 = 7
15 - 6 = 9,
15 - 8 =7,
15 - 7 = 8,
15 - 9 = 6
Tính hợp lý:
a) (-7/15) * 5/8 * (15/-7) * (-16)
b) (-1/3) * (-15/17) * 34/45
c) (-5/6 ) * 4/19 + ( -7/12 ) * 4/19
=(-7/15.15-7) . (5/8 . -16)
= 1 . -10 = -10
tính nhanh
a) -5/12+4/37+17/12-41/37
b) 1/2+-3/5:(-1/1/2)-|-2/5|
c)8^15 x 3^16/4^22 x 9^8
d)35/1/6:(-4/5)-45/1/6:(-4/5)
e) (5/12:10/3)+(1/2)^2
a, \(\frac{-5}{12}+\frac{4}{37}+\frac{17}{12}-\frac{41}{37}\)
\(=\left(-\frac{5}{12}+\frac{17}{12}\right)+\left[\frac{4}{37}+\left(-\frac{41}{37}\right)\right]\)
\(=1+\left(-1\right)\)
\(=-1\)
b, \(\frac{1}{2}+\left(-\frac{3}{5}\right):\left(-1\frac{1}{2}\right)-\left|-\frac{2}{5}\right|\)
\(=\frac{1}{2}+\left(-\frac{3}{5}\right):\left(-\frac{3}{2}\right)-\frac{2}{5}\)
\(=\frac{1}{2}+\frac{2}{5}-\frac{2}{5}\)
\(=\frac{1}{2}\)
Mấy bài còn lại tương tự bn tự làm nha tính số mũ ra xong thực hiện, lấy thừa số chung mà nhân ( H mik bận đi hc thêm rồi)
Tính a)16/13-(3/15-6/13)
b)21/8-(1/2+3/5)
c)3/2x9/5-3-2x2/7
d)32/45x18/16
e)(4/3-4/5)x25/2
f)2-1/3-1/2-1/6-3/12
a)\(=\dfrac{16}{13}-\dfrac{3}{15}+\dfrac{6}{13}=\dfrac{22}{13}-\dfrac{3}{15}=\dfrac{96}{65}\)
b)\(=\dfrac{21}{8}-\left(\dfrac{5}{10}+\dfrac{6}{10}\right)=\dfrac{21}{8}-\dfrac{11}{10}=\dfrac{61}{40}\)
c)\(=\dfrac{27}{10}-3-\dfrac{4}{7}--\dfrac{61}{70}\)
d)\(=\dfrac{576}{702}=\dfrac{4}{5}\)
e)\(=\left(\dfrac{20}{15}-\dfrac{12}{15}\right)\times\dfrac{25}{2}=\dfrac{8}{15}\times\dfrac{25}{2}=\dfrac{20}{3}\)
f)\(=\dfrac{24}{12}-\dfrac{4}{12}-\dfrac{6}{12}-\dfrac{2}{12}-\dfrac{3}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)
d) \(=\dfrac{32}{45}x\dfrac{18}{16}=\dfrac{576}{720}=\dfrac{115}{114}\)
e) \(=\left(\dfrac{4}{3}-\dfrac{4}{5}\right)x\dfrac{25}{12}=\dfrac{8}{15}x\dfrac{25}{12}=\dfrac{200}{180}=\dfrac{10}{9}\)
f) \(=\dfrac{2}{1}-\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{1}{6}-\dfrac{3}{12}=\dfrac{24}{12}-\dfrac{4}{12}-\dfrac{6}{12}-\dfrac{2}{12}-\dfrac{3}{12}\)
\(=\dfrac{20}{12}-\dfrac{4}{12}-\dfrac{3}{12}=\dfrac{16}{12}-\dfrac{3}{12}=\dfrac{13}{12}\)
Bài 1: Thực hiện phép tính:
a, \(\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)
b, \(\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}\)
c, \(\dfrac{\dfrac{1}{9}-\dfrac{5}{6}-4}{\dfrac{7}{12}-\dfrac{1}{36}-10}\)
\(a,\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right).\)
\(=\left(\dfrac{21}{60}+\dfrac{44}{60}-\dfrac{75}{60}\right):\left(\dfrac{99}{180}-\dfrac{104}{180}\right).\)
\(=\left(\dfrac{65}{60}-\dfrac{75}{60}\right):\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{10}{60}:\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{1}{6}:\left(-\dfrac{1}{36}\right).\)
\(=-\dfrac{1}{6}.\left(-36\right).\)
\(=\dfrac{-1.\left(-36\right)}{6}=\dfrac{36}{6}=6.\)
Vậy......
\(b,\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}.\)
\(=\dfrac{5\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}{8\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}:\dfrac{15\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}{16\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}.\)
\(=\dfrac{5}{8}:\dfrac{15}{16}.\)
\(=\dfrac{5}{8}.\dfrac{16}{15}=\dfrac{5.16}{8.15}=\dfrac{1.2}{1.3}=\dfrac{2}{3}.\)
Vậy......
c, (làm tương tự câu b).
~ Học tốt!!! ~
Tính hợp lí:
a,[15:(-3)+40:(-8)]-3(16:8)
b,3(25:5-14:2)-5(6:2)
c,[-15:(-3)]-3[2.(5-9:3)]
d,-2(-3+8:2-7)-5.4
e,7.[-6:2-15:(-3)-3]
f,17.(-84)+17.(-16)
a,[15:(-3)+40:(-8)]-3(16:8)
= ( - 5 - 5 ) - 3. 2
= - 10 - 6
= - 16
b, 3 ( 25 : 5 - 14 : 2 ) - 5 ( 6 : 2 )
= 3 . (5 - 7 ) - 5 . 3
= 3 . - 2 - 5 . 3
= - 21
c, [ - 15 : ( - 3 ) ] - 3 [ 2. ( 5 - 9 : 3 ) ]
= 5 - 3 . 4
= - 7
d, - 2 ( - 3 + 8 : 2 - 7 ) - 5 . 4
= - 2 . - 6 - 5 . 4
= 12 - 20
= - 8
e, 7 . [ - 6 : 2 - 15 : ( - 3 ) - 3 ]
= 7 . ( - 3 + 5 - 3)
= - 7
f, 17 . ( - 84 ) + 17 . ( - 16)
= - 1428 - 272
= - 1700
a,[15:(-3)+40:(-8)]-3(16:8)
= ( - 5 - 5 ) - 3. 2
= - 10 - 6
= - 16
b, 3 ( 25 : 5 - 14 : 2 ) - 5 ( 6 : 2 )
= 3 . (5 - 7 ) - 5 . 3
= 3 . - 2 - 5 . 3
= - 21
c, [ - 15 : ( - 3 ) ] - 3 [ 2. ( 5 - 9 : 3 ) ]
= 5 - 3 . 4
= - 7
d, - 2 ( - 3 + 8 : 2 - 7 ) - 5 . 4
= - 2 . - 6 - 5 . 4
= 12 - 20
= - 8
e, 7 . [ - 6 : 2 - 15 : ( - 3 ) - 3 ]
= 7 . ( - 3 + 5 - 3)
= - 7
f, 17 . ( - 84 ) + 17 . ( - 16)
= - 1428 - 272
= - 1700
bài 1 : tính phân số:
a) \(\frac{5}{7}+\frac{4}{9}=?;\frac{4}{5}-\frac{2}{3}=?;\frac{9}{11}+\frac{3}{8}=?;\frac{16}{25}-\frac{2}{5}=?\)=?
b)\(5+\frac{3}{5}=?;10-\frac{9}{16}=?;\frac{2}{3}-\left(\frac{1}{6}+\frac{1}{8}\right)=?\)
c)\(\frac{5}{7}+\frac{7}{6}=?;\frac{7}{12}+\frac{17}{18}=?;\frac{9}{8}+\frac{15}{32}=?;4+\frac{35}{45}=?\)
d)\(\frac{11}{4}-\frac{15}{16}=?;\frac{5}{6}-\frac{5}{8}=?;\frac{196}{64}-2=?;3-\frac{13}{9}=?\)
e)\(\frac{8}{5}+\frac{7}{6}+\frac{5}{9}-2=?;3-\frac{5}{6}-\frac{4}{9}+\frac{32}{24}=?\)
a)\(\dfrac{5}{7}+\dfrac{4}{9}=\dfrac{45}{63}+\dfrac{28}{63}=\dfrac{73}{63}\) ; \(\dfrac{9}{11}+\dfrac{3}{8}=\dfrac{72}{88}+\dfrac{33}{88}=\dfrac{105}{88}\)
\(\dfrac{4}{5}-\dfrac{2}{3}=\dfrac{12}{15}-\dfrac{10}{15}=\dfrac{2}{15}\); \(\dfrac{16}{25}-\dfrac{2}{5}=\dfrac{16}{25}-\dfrac{10}{25}=\dfrac{6}{25}\)