Tính nhanh :
a)8 x 45 + 55 x 8
= 8x(45+55)
= 8x100
=800
28 x 69 + 31 x 28
= 28x(69+31)
= 28x100
=2800
Ta có :
8 x 45 + 55 x 8
= 8 x ( 45 + 55 )
= 8 x 100
= 800
28 x 69 + 31 x 28
= 28 x ( 69 + 31 )
= 28 x 100
= 2800
8 x 45 + 55 x 8
= 8 x ( 45 + 55 )
= 8 x 100
= 800
1) \(8\cdot45+55\cdot8\)
\(=8\cdot\left(45+55\right)\)
\(=8\cdot100\)
\(=800\)
2) \(28\cdot69+31\cdot28\)
\(=28\cdot\left(69+31\right)\)
\(=28\cdot100\)
\(=2800\)
a) \(8\times45+55\times8\)
\(=8\times\left(45+55\right)\)
\(=8\times100\)
\(=800\)
b) \(28\times69+31\times28\)
\(=28\times\left(69+31\right)\)
\(=28\times100\)
\(=2800\)
8 x 45 + 55 x 8
= 8 x (45 + 55)
= 8 x 100
= 800
28 x 69 + 31 x 28
= 28 x (69 + 31)
= 28 x 100
2800
8 x 45 + 55 x 8
=8 x (45+55)
=8 x 100
=800
28 x 69 + 31 x 28
=28 x ( 69+31)
=28 x 100
=2800
giúp mình nha
