Bài 2: Tính nhanh

a) 29 + 132 + 237 + 868 + 3

 = 29+(132+858)+(237+3)

=29+990+240

=1259

hình như bạn làm sai á

a ) 1 12 + 2 3 + − 3 4 = 1 12 + 8 12 + − 9 12 = 0

b ) 1 2 − 2 5 + − 7 10 = 5 10 − 4 10 + − 7 10 = − 6 10 = − 3 5 c ) 1 2 + − 3 7 + 5 2 + − 4 7 = 1 2 + 5 2 + − 3 7 + − 4 7 = 2 d ) 9 8 − 4 7 + − 1 8 + 11 7 = 9 8 + − 1 8 + − 4 7 + 11 7 = 2 e ) 6 11 + − 2 3 + 5 11 = 6 11 + 5 11 + − 2 3 = 1 3 f ) − 1 2 + 11 4 − 11 4 − 1 2 = − 1 2 + 11 4 − 11 4 + 1 2 = 0

alo 

a) \(3.5^2+15.2^2-26\div2\)

= 3.25 + 15.4 - 13

= 75 + 60 - 13

= 135 - 13

= 122

b) \(5^3.2-100\div4+2^3.5\)

= 125.2 - 25 + 8.5

= 250 - 25 + 40

= 225 + 40

= 265

c)\(6^2\div9+50.2-3^3.33\)

= 36 : 9 + 100 - 9.33

= 4 + 100 - 297

= 104 - 297

= -193

d)\(3^2.5+2^3.10-81\div3\)

= 9.5 + 8.10 - 27

= 45 + 80 - 27

= 125 - 27

= 98

e) \(5^{13}\div5^{10}-25.2^2\)

= 5³ - 25.4

= 125 - 100

= 25

f) \(20\div2^2+5^9\div5^8\)

= 20 : 4 + 5

= 5 + 5

= 10

a: \(2\cdot25\cdot4\cdot50\)

\(=\left(2\cdot50\right)\cdot\left(25\cdot4\right)\)

\(=100\cdot100=10000\)

b: \(\left(-125\right)\cdot5\cdot\left(-16\right)\cdot\left(-8\right)\)

\(=-125\cdot5\cdot16\cdot8\)

\(=-\left(125\cdot8\right)\cdot\left(5\cdot16\right)\)

\(=-80\cdot1000=-80000\)

c: \(5^2\cdot3^3\cdot2\)

\(=25\cdot27\cdot2\)

\(=\left(25\cdot2\right)\cdot27=27\cdot50=1350\)

d: \(\left(-4\right)\cdot3^2\left(-5\right)^3\)

\(=\left(-4\right)\cdot\left(-125\right)\cdot9\)

\(=500\cdot9=4500\)