Question

Câu 19: Tính tổng sau một cách hợp lí: a) (-37) + 14 + 26 + 37 b) (-24) + 6 + 10 + 24 c) 15 + 23 + (-25) + (-23) d) 34 + 35 + 36 + 37 – 14 – 15 – 16 – 17 e) 35 . 43 + 35 . 56 + 35. f) 29 . 87 – 29 . 23 + 64 . 71. k) 37.24 + 37.76 + 63.79 + 21.63 l) (-36).43 + (-36).57

Answer 1

a: \(\left(-37\right)+14+26+37\)

=(-37+37)+(14+26)

=0+40

=40

b: \(\left(-24\right)+6+10+24\)

=(-24+24)+(6+10)

=0+16

=16

c: \(15+23+\left(-25\right)+\left(-23\right)\)

\(=\left(15-25\right)+\left(23-23\right)\)

=-10+0

=-10

d: \(34+35+36+37-14-15-16-17\)

\(=\left(34-14\right)+\left(35-15\right)+\left(36-16\right)+\left(37-17\right)\)

=20+20+20+20

=80

e: \(35\cdot43+35\cdot56+35\)

\(=35\left(43+56+1\right)\)

\(=35\cdot100=3500\)

f: \(29\cdot87-29\cdot23+64\cdot71\)

\(=29\left(87-23\right)+64\cdot71\)

\(=29\cdot64+64\cdot71\)

\(=64\left(29+71\right)\)

\(=64\cdot100=6400\)

k: \(37\cdot24+37\cdot76+63\cdot79+21\cdot63\)

\(=37\left(24+76\right)+63\left(79+21\right)\)

\(=100\left(63+37\right)\)

\(=100\cdot100=10000\)

l: \(\left(-36\right)\cdot43+\left(-36\right)\cdot57\)

\(=\left(-36\right)\cdot\left(43+57\right)\)

\(=-36\cdot100=-3600\)