Toán Lớp 4: Tính bằng hai cách: a) 12x 45 + 12x 55 b) 3913 x 15 –3913 x 5 c) 2712 x (6 + 24)

Question

Toán Lớp 4:  Tính bằng hai cách:             a) 12x 45 + 12x 55                b) 3913 x 15 –3913 x 5                      c) 2712 x (6 + 24)                                                                                                       d) 9715 x (74 –24)

hoquyly · Answer

a. C1   12 x 45 + 12 x 55   = 12 x ( 45 + 55 )   = 12 x 100   = 1200   C2   12 x 45 + 12 x 55   = 540 + 660   = 1200   b. C1   3913 x 15 - 3913 x 5   = 3913 x ( 15 - 5 )   = 3913 x 10   = 39130   C2   3913 x 15 - 3913 x 5   = 58695 - 19565   = 39130   c. C1   2712 x ( 6 + 24 )   = 2712 x 30   = 81360

diepbich93 · Answer

Lời giải chi tiết:     a) C&aacute;ch 1:   12xx45+12xx55   =540+660   =1200   C&aacute;ch 2:   12xx45+12xx55   =12xx(45+55)   =12xx100   =1200   a) C&aacute;ch 1:   3913xx15-3913xx5   =58695-19565   =39130   C&aacute;ch 2:   3913xx15-3913xx5   =3913xx(15-5)   =3913xx10   =39130   c) C&aacute;ch 1:   2712xx(6+24)   =2712xx30   =81360   C&aacute;ch 2:   2712xx(6+24)   =2712xx6+2712xx24   =16272+65088   =81360   d) C&aacute;ch 1:   9715xx(74-24)   =9715xx50   =485750   C&aacute;ch 2:   9715xx(74-24)   =9715xx74-9715xx24   =718910-233160   =485750   @uniquetimehunter