Câu 20 không cần làm hả bạn?

a,33-14-26-(-7)=33-14-26+7=19-26+7=(-7)+7=0

b,(-5)-25-(-34)-4=(-5)-25+34-4=(-30)+34-4=4-4=0

c,(-6)+5+(-4)+25=(-6)+5-4+25=(-1)+5-4+25=4-4+25=25

d,33+34+35+35+36-13-14-15-16=(33-13)+(34-14)+...+(36-16)

                                                     =20+20+20+20+20

                                                      =100

Bài 21
a, \(33-14-26-\left(-7\right)\)
\(=33+7-14-26\)
\(=40-14-26\)
\(=26-26=0\)

b, \(\left(-5\right)-25-\left(-34\right)-4\)
\(=\left(-5\right)+\left(-25\right)+34-4\)
\(=-30+30=0\)

c,\(\left(-6\right)+5+\left(-4\right)+25 \)
\(=\left(-6\right)+\left(-4\right)+\left(5+25\right)\)
\(=-10+30=20\)

d, \(33+34+35+36-13-14-15-16\)
\(=\left(33-13\right)+\left(34-14\right)+\left(35-15\right)+\left(36-16\right)\)
\(=20+20+20+20=80\)

21. didn’t go

22. isn’t painting

23. aren’t planting

24. Are they making

25. is repairing

26. is taking

27. is explaining

28. is studying

29. tries/ don’t think

30. passes

21. didn’t go

22. isn’t painting

23. aren’t planting

24. Are they making

25. is repairing

26. is taking

27. is explaining

28. is studying

29. tries/ don’t think

30. passes

D

số 512 bên cạnh câu 21 là nhân hay bỏ nhầm vậy?

d

\(\frac{5,4:0,4\times1420+4,5\times780\times3}{3+6+9+12+15+18+21+24+27}\)

\(=\frac{13,5\times1420+13,5\times780}{\left(3+27\right)+\left(6+24\right)+\left(9+21\right)+\left(12+18\right)+15}\)

\(=\frac{13,5\times\left(1420+780\right)}{30+30+30+30+15}\)

\(=\frac{13,5\times2200}{135}\)

\(=\frac{29700}{135}\)

\(=220\)

1m25cm=125cm

1m25cm=1,25m

0,02

0,35

0,024

0,02

7,0068

6,5

1,25

10025

0,25

0,45

0,78

0,35

13025

0,438

0,02

0,35

0,024

0,02

7,0068

6,5

1,25

10025

0,25

0,45

0,78

0,35

13025

0,438

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