Question

Tính nhanh: a) 0,125 + 21,075 + 88,36 + 9,875 + 78,925 + 11,64 b) 3457 - 27 x 48 - 48 x 73 + 6543 c) (792,81 0,25 + 792,81 0,75) (11x 9 – 900 x 0,1 - 9)

Answer 1

Tính nhanh:

a) 0,125 + 21,075 + 88,36 + 9,875 + 78,925 + 11,64

= \((0,125+9,875)+(21,075+78,925)+(88,36+11,64)\)

= \(10+100+100\)

= \(210\)

b) 3457 - 27 . 48 - 48 . 73 + 6543

= \((3457 +6543) - (27 . 48 + 48 . 73)\)

\(= 10000 - 48 . (27 + 73) \)

\(= 10000-48.100\)

\(= 10000 - 4800\)

\(= 5200\)

c) (792,81. 0,25 + 792,81 0,75). (11. 9 – 900 . 0,1 - 9)

= [ 792,81 . ( 0,25 + 0,75 ) ] . ( 99 - 90 - 9 )

= [ 792,81 . 1 ] . ( 9 - 9)

= 792,81 . 0

= 0