Question

Bài 5. Tính hợp lí

1, 35.18-5.7.28

2, 45-5 .( 12+9)

3, 24.(16-5)-16.(24-5)

4, 29.(19-13)-19.(29-13)

5., 31.(-18)+31.(-81)-31

6, (-12).47+(-12).52+(-12)

7, 13.(23+22)-3.(17+28)

8, -48+48(-78)+48.(-21)

Giúp mình với mai nộp rồi

Tank you bạn nhiều nhé♡◇♡♡♡

Answer 1

1) 35.18 - 5.7.28

= 35.18 - 35.28

= 35.(18 - 28)

= 35.(-10)

= -350

2) 45 - 5.(12 + 9)

= 45 - 5.12 - 5.9

= 45 - 60 - 45

= (45 - 45) - 60

= 0 - 60

= -60

3) 24.(16 - 5) - 16.(24 - 5)

= 24.16 - 24.5 - 16.24 + 16.5

= (24.16 - 16.24) - (24.5 + 16.5)

= 0 - (24.5 + 16.5)

= -24.5 + 16.5

= 5.(-24 + 16)

= 5.(-8)

= -40

4) 29.(19 - 13) - 19.(29 - 13)

= 29.19 - 29.13 - 19.29 + 19.13

= (29.19 - 19.29) + (19.13 - 29.13)

= 0 + (19.13 - 29.13)

= 19.13 - 29.13

= 13.(19 - 29)

= 13.(-10)

= -130

5) 31.(-18) + 31.(-81) - 31

= 31.(-18 - 81 - 1)

= 31.(-100)

= -3100

6) (-12).47 + (-12).52 + (-12)

= (-12).(47 + 52 + 1)

= (-12).100

= -1200

7) 13.(23 + 22) - 3.(17 + 28)

= 13.45 - 3.45

= 45.(13 - 3)

= 45.10

= 450

8) -48 + 48.(-78) + 48.(-21)

= 48.(-1) + 48.(-78) + 48.(-21)

= 48.(-1 - 78 - 21)

= 48.(-100)

= -4800

Answer 2

đợi chút xíu nhé!

Answer 3

Chúc nguyễn làm đúng rồi!

Answer 4

1. 35 x 18 - 5 x 7 x 28

= 35 x 18 - (5 x 7) x 28

= 35 x 18 - 35 x 28

= 35 x (18 - 28)

= 35 x (-10)

= -350

2. 45 - 5 x (12 + 9)

= 45 - (5 x 12 + 5 x 9)

= 45 - (5 x 9 + 5 x 12)

= 45 - (45 + 60)

= 45 - 105

= -60

3. 24 x (16 - 5) - 16 x (24 - 5)

= (24 x 16 - 24 x 5) - (16 x 24 - 16 x 5)

= (24 x 16 - 16 x 24) - (24 x 5 - 16 x 5)

= 0 - (24 x 5 - 16 x 5)

= 0 - (120 - 80)

= 0 - 40

= -40

4. 29 x (19 - 13) - 19 x (29 - 13)

= (29 x 19 - 29 x 13) - (19 x 29 - 19 x 13)

= (29 x 19 - 19 x 29) - (29 x 13 - 19 x 13)

= 0 - (29 x 13 - 19 x 13)

= 0 - (10 x 13)

= 0 - 130

= -130

5. 31 x (-18) + 31 x (-81) - 31

= 31 x -(18 + 81) - 31

= 31 x (-99) - 31

= 31 x -(99 + 1)

= 31 x (-100)

= -3100

6. (-12) x 47 + (-12) x 52 + (-12)

= (-12) x (47 + 52) + (-12)

= (-12) x 99 + (-12)

= (-12) x (99 + 1)

= (-12) x 100

= -1200

7. 13 x (23 + 22) - 3 x (17 + 28)

= 13 x 45 - 3 x 45

= (13 - 3) x 45

= 10 x 45

= 450

8. -48 + 48 x (-78) + 48 x (-21)

= -48 + (-48) x 78 + (-48) x 21

= -48 + (-48) x (78 + 21)

= -48 + (-48) x 99

= -48 x (99 + 1)

= -48 x 100

= -4800