Bài 4:
a) 12. 53 + 53. 172 - 53. 84
= 53.(12 + 172 - 84)
= 53. 100
= 5300
b) 53. 35. 13 + 35. 17 + 65. 75 - 65. 45
= 35.(53. 13 + 17) + 65.(75 - 45)
= 35.(689 + 17)+ 65. 30
= 35. 706 + 1950
= 24710 + 1950
= 26660
c) 23. 15 - [115 - (12 - 5)2]
= 8. 15 - (115 - 72)
= 120 - (115 - 49)
= 120 - 66
= 54
d) 32. 22 - 32. 19
= 32.(22 - 19)
= 9. 3
= 27
a) 12 . 53 + 53 . 172 + 53 . 84
= 53 . (12 + 172 - 84)
= 53 . 100
= 5300
b) 53 . 35 . 13 + 35 . 17 + 65 . 75 - 65 . 45
= 35 . (53 . 13 + 17) + 65 . (75 - 45)
= 35 . 706 + 65 . 30
= 24710 + 950
= 26660
c) 23 . 15 - [ 115 - (12 - 5)2 ]
= 8 . 15 - (115 - 72)
= 120 - 115 + 49
= 5 + 49
= 54
d) 32 . 22 - 32 . 19
= 32 . (22 - 19)
= 32 . 3
= 33
= 27