a) \(\text{2459 - (400 + 459)}\)
\(\text{= 2459 - 859}\)
\(\text{= 1600}\)
b) \(435\times25+76\times435-435\)
\(=435\times\left(25+76-1\right)\)
\(=435\times100\)
\(=43500\)
c) \(35\times49+51\times36\)
\(=35\times49+51\times\left(35+1\right)\)
\(=35\times49+51\times35+51\)
\(=35\times\left(49+51\right)+51\)
\(=35\times100+51\)
\(=3500+51\)
\(=3551\)
a) 2459 - (400 + 459)
= 2459 - 400 - 459
= (2459 - 459) - 400
= 2400 - 400
= 2000
b) 435 x 25 + 76 x 435 - 435
= 435 x (25 + 76 - 1)
= 435 x 100
= 43500
c) 35 x 49 + 51 x 36
= 1715 + 1836
= 3551
a:2459 - (400+459)
=2459 - 400 + 459
=(2459 -459) - 400
=2000-400 = 1600
Tính nhanh
a : 2459 - ( 400 + 459 )
= 2459 - 400 - 459
= 2459 - 459 - 400
= 2000 - 400
= 1600
b : 435 x 25 + 76 x 435 - 435
= 435 x ( 25 + 76 - 1 )
= 435 x 100
= 43500
c : 35 x 49 + 51 x 36
= 35 x 49 + 51 x ( 35 + 1 )
= 35 x 49 + 51 x 35 + 51
= 35 x ( 49 + 51 ) + 51
= 35 x 100 + 51
= 3500 + 51
= 3551
Hok tốt
