Question

[hung phung]

Thực hiện phép tính ( tính nhanh nếu có thể)
a) (2345 + 45) - 2345                                 b) (-2010) - (119 - 2010)
c) (18 + 29) + (158 - 18 - 29)                     d) 126 + (-20) + 2004 + (-106)
e) (-199) + (-200) + (201)                           f) 99 + (-100) + 101
g) 217 + [ 43 + (-217) + (-23)]

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(\left(2345+45\right)-2345\)

\(=2345+45-2345\)

\(=45+\left(2345-2345\right)\)

=45+0

=45

b: \(\left(-2010\right)-\left(119-2010\right)\)

\(=-2010-119+2010\)

\(=\left(-2010+2010\right)-119\)

=0-119

=-119

c: \(\left(18+29\right)+\left(158-18-29\right)\)

\(=18+29+158-18-29\)

\(=158+\left(18-18\right)+\left(29-29\right)\)

=158+0+0

=158

d: \(126+\left(-20\right)+2004+\left(-106\right)\)

\(=126-20+2004-106\)

\(=\left(126-20-106\right)+2004\)

=0+2004

=2004

e: \(\left(-199\right)+\left(-200\right)+\left(201\right)\)

\(=-199-200+201\)

\(=-199+\left(201-200\right)\)

=-199+1

=-198

f: \(99+\left(-100\right)+101\)

\(=\left(99+101\right)-100\)

=200-100

=100

g: \(217+\left[43+\left(-217\right)+\left(-23\right)\right]\)

\(=217+43-217-23\)

\(=\left(217-217\right)+\left(43-23\right)\)

=0+20

=20

Answer 2

[hung phung]

thank you very much