a)

-37 +14 +26+37=(-37+37)+(14+26)=30

b) =(-24+24)+(6+10)=16

c)=(-23+23)+(25+15)=40

d)=(-33+33)+(-50+60)=10

e)=(-209+209)+[-14+(-16)]=-30

1) ( - 37 ) + 14 + 26 + 37

= ( - 37 + 37 ) + 14 + 26

= 0 + 40

= 40

2) ( - 24 ) + 6 + 10 + 24

= ( - 24 + 24 ) + 6 + 10

= 0 + 16

= 16

3) 15 + 23 + ( - 25 ) + ( - 23 )

= ( 23 - 23 ) + ( 15 - 25 )

= 0 - 10

= - 10

4) 60 + 33 + ( - 50 ) + ( - 33 )

= ( 60 - 50 ) + ( 33 - 33 )

= 10 + 0

= 10

( - 16 ) + ( - 209 ) + ( - 14 ) + 209

= ( - 16 - 14 ) + ( - 209 + 209 )

= - 30 + 0

= - 30

a, \(46-57+111\)

\(=-11+111\)

\(=100\)

\(16.40-8.20.2\)

\(=16.40-\left(2.20\right).8\)

\(=16.40-40.8\)

\(=40\left(16-8\right)=40.8=320\)

\(24\left(16-30\right)-16\left(24-30\right)\)

\(=24.16-24.30-16.24+16.30\)

\(=\left(24.16-16.24\right)-30.\left(24-16\right)\)

\(=-30.8=-240\)

\(19+18+17+16+14+21+22+23+24+25+26\)

\(=\left(19+21\right)+\left(18+22\right)+\left(17+23\right)+\left(16+24\right)+\left(14+26\right)+25\)

\(=30+30+30+30+30+25\)

\(=175\)

\(\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{4}{6}+\dfrac{9}{12}+\dfrac{16}{20}\)

\(=\dfrac{1}{3}+\dfrac{1}{4}+\dfrac{1}{5}+\dfrac{2}{3}+\dfrac{3}{4}+\dfrac{4}{5}\)

\(=\left(\dfrac{1}{3}+\dfrac{2}{3}\right)+\left(\dfrac{1}{4}+\dfrac{3}{4}\right)+\left(\dfrac{1}{5}+\dfrac{4}{5}\right)\)

\(\text{=}1+1+1\)

\(\text{=}3\)

=-3720

đồ bấm máy tính ko chấp

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31

+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+4

7+48+49+50-999-888-777-666-555-444-333-222-111= -3720

áp dụng kiến thức tính nhanh ý

1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50=1275

= 1275

=1275

=1245

Có ai rảnh đâu mà đi ngồi cộng ngần đấy số ra.