tính bằng cách nhanh nhất:
35x7-70+35x5
=...................................................................
=...................................................................
=...................................................................
=...................................................................
35x7-70+35x5
= 35 x 7 - 35 x 2 + 35 x 5
= 35 x ( 7-2+5)
= 35 x 10
= 350
35 x 7 - 70 + 35 x 5
= 35 x 7 - 35 x 2 + 35 x 5
= 35 x ( 7 - 2 + 5 )
= 35 x 10
= 350
35x7-70+35x5
=35x7-35x2+35x5
=35x[7-2+5]
=35x10
=350
