a: =8h52p

b: =484p-166p=318p

c: =10p

d: =4,45s

giúp mình ạ!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

a] \(68141:4=17035,25\)

b] \(39786:9=4420,666667\)

c] \(89689:8=11211,125\)

d] \(84678:6=14113\)

a, 249 - 25 × 8 + 3² ×  4

= 249 - 200 + 9 × 4

= 49 + 36

= 85

b,27 : { 480 :  [(513 : 9 + 19 ) + 84 ]}

= 27 : { 480 : [(57 + 19) + 84 ]}

= 27 : { 480 : [76 + 84]}

= 27 : { 480 : 160}

= 27 : 3

= 9

c. 73 × 25 + 28 × 25 - 25 

= 73 × 25 + 28 × 25 - 25 × 1

= 25 × (73 + 28 - 1)

= 25 × 100

= 2500

d. 2× 9 × 50 - 89⁰

= (2 × 50) × 9 - 1

= 100 × 9 - 1

= 900 - 1

= 899

a)\(249-25\cdot8+3^2\cdot4\)

\(=249-200+9\cdot4\)

\(=49+36=85\)

b)\(27:\left\{480:\left[\left(513:9+19\right)+84\right]\right\}\)

\(=27:\left\{480:\left[\left(57+19\right)+84\right]\right\}\)

\(=27:\left\{480:\left[76+84\right]\right\}\)

\(=27:\left\{480:160\right\}\)

\(=27:3=9\)

c)\(73\cdot25+28\cdot25-25\)

\(=73\cdot25+28\cdot25-25\cdot1\)

\(=\left(73+28-1\right)\cdot25\)

\(=100\cdot25=2500\)

d)\(2\cdot9\cdot50-89^0\)

\(=2\cdot9\cdot50-1\)

\(=900-1=899\)

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{457}\\{452}\end{array}}\\\hline{\,\,\,907}\end{array}\)                               \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{326}\\{\,\,29}\end{array}}\\\hline{\,\,\,355}\end{array}\)

\(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{762}\\{184}\end{array}}\\\hline{\,\,\,946}\end{array}\)                               \(\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{546}\\{172}\end{array}}\\\hline{\,\,\,718}\end{array}\)

Câu 3 : Tính

a) 74,15 + 4,05 : 2,5

= 74,15 + 1,62 

= 75,77

b) 100 - 2,6 x 3,9 + 20,97 

= 100 - 10,14 + 20,97 = 110,83

Câu 4: Tính nhanh

a) \(\dfrac{1}{2}\) + \(\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}\)

= 2 x (1 - 1/2 + 1/2 - 1/4 + 1/4 - 1/8 + 1/8 - 1/16 + 1/16 - 1/32 + 1/32 - 1/64)

= 2 x (1 - 1/64)

= 2 x 63/64

= 63/32

- Phần còn lại mình sẽ làm sau nhé bạn!

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#Toán-5

Câu 3:

a, 74,15 + 4,05 : 2,5

= 74,15 + 1,62

= 75,77

b, 100 - 2,6 x 3,9 + 20,97

= 100 - 10,14 + 20,97

= 89,86 + 20,97

= 110,83

533 + 128 = 661

728 - 245 = 483

172 x 4 = 688

798 : 7 = 114

Kết quả lần lượt là: 660 ; 483 ; 684 ; 112

cái phép 171*4 khó nghê

đáy : \(\dfrac{72+8}{2}=40\left(m\right)\)

chiều cao : \(40-8=32\left(m\right)\\ S=40\times32=1220\left(m^2\right)\)