a) 5+8+11+14+...+38+41.(13 số hạng )

=(5+41)+(8+38)+(11+35)...+(20+26)+23(6 cặp )

=46+46+46+...+46+23

=46x6+23=276+23=299

b)5219+6998

=12217

c)4996+2314+1003

=(4996+2314)+1003

=7310+1003=8313

8313 click cho nhé

a) 639 + 1999

= (639 - 1) + (1999 + 1)

= 638 + 2000

= 2638

b) 5219 + 6998

= (5219 - 2) + (6998 + 2)

= 5217 + 7000

= 12217

c) 4996 + 2314 + 1003 

= (4996 + 4) + (2314 - 4) + 1000 + 3

= 5000 + 2310 + 1000 + 3

= (5000 + 1000) + (2310 + 3)

= 6000 + 2313

= 8313

a/1999 + (1+638)

=2000+638

=2638

có ai làm đc kkkông

a ) 2 1 4 : 3 5 4 = 9 4 : 17 4 = 9 4 . 4 17 = 9 17

b ) − 3 1 7 : − 2 3 14 = − 22 7 : − 31 7 = 22 31

a) \(\left(-48\right)+10+\left(-22\right)+\left(-10\right)\)

\(=\left[\left(-48\right)+\left(-22\right)\right]+\left(-10+10\right)\)

\(=-70+0=-70\)

Tham khảo <3

= -70 

( hihi )

h giup minh voi

a) 4x+6=3x-4

<=>4x-3x=-4-6

<=>x=-10

a)Tìm x:

4x+6=3x-4

4x-3x=-4-6

       x=-10

Vậy x=-10

c)Tính nhanh:

2315.(-2314+1)-2314.(1-2315)

=2315.(-2314)+2315-2314-2314.2315

=2315.(-2314+1-2314)-2314

=2315.(-4627)-2314

=-10711505-2314

=-10713819

làm giúp😢😢

a) 425.7.4-170.60

=85.5.7.4-85.2.60=85.(5.7.4-2.60)=85.20=1700