Bài 15: Tính hợp lí:
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
1; (15 + 22) + (135 - 15 - 22)
= 15 + 22 + 135 - 15 - 22
= (15 - 15) + (22 - 22) + 135
= 0 + 0 + 135
= 135
![](https://rs.olm.vn/images/avt/0.png?1311)
(36.15.169) : (5.18.13) = 91260 : ( 5.18.13) = 91260 : 1170 =78 k mình nha bạn
![](https://rs.olm.vn/images/avt/0.png?1311)
-5 + (-37 - 45 + 51) - (-37 + 51)
= -5 - 37 - 45 + 51 + 37 - 51
= - (5 + 45) - (37 - 37) + (51 - 51)
= - 50 - 0 + 0
= - 50
- (15 - 47 + 58) + (15 - 47 ) + 3
= - 15 + 47 - 58 + 15 - 47 + 3
= (-15 + 15) + (47 - 47) - (58 - 3)
= 0 + 0 - 55
= - 55
(53 - 45 - 49) - (53 + 45 - 49)
= 53 - 45 - 49 - 53 - 45 + 49
= (53 - 53) + (-49 + 49) - (45 + 45)
= 0 + 0 - 90
= - 90
13 - 15 + 49 - 13 + 15 - 48
= (13 - 13) + (-15 + 15) + (49 - 48)
= 0 + 0 + 1
= 1
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{45.21.25}{7.15.36}=\dfrac{3.3.3.5.7.5.5}{7.5.3.3.2.3.2}=\dfrac{25}{4}\)
45\7 x 21\15 x 25/36
=45x21x25/7x15x36
=15x3x7x3x25/7x15x3x12
=3x25/12
=75/12
=25/4
![](https://rs.olm.vn/images/avt/0.png?1311)
3/4×13/21-3/21×7/4+15/4×3/21
= 3/21 x 13/4 - 3/21 x 7/4 + 15/4 x 3/21
= 3/21 x ( 13/4 - 7/4 + 15/4 )
= 3/21 x 21/4
= 3/4
3/4 x 13/21 - 3/21 x 7/4 + 15/4 x 3/21
= 3/21 x 13/4 - 3/21 x 7/4 + 15/4 + 3/21
= 3/21 x ( 13/4 - 7/4 + 15/4 )
= 3/21 x 21/4
= 3/4
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\dfrac{-15}{8}\) x \(\left(\dfrac{8}{15}+\dfrac{32}{27}\right)\)
= \(\dfrac{-15}{8}\) x \(\dfrac{232}{135}\)
= \(\dfrac{-29}{9}\)
a)A=158x(168-58):11:10
=158x(110:11:10)
=158x1
=158
b)
( 456 x 11 + 912 ) x 37 : ( 13 x 74 )
( 456 x 11 + 192 ) x 37 : 13 x 37 x 2
= ( 456 x 11 + 456 x 2 ) x 37 : 13 x 37 x 2
= ( 456 x ( 11 + 2 ) x 37
= 456 x 17 x 37 : 13 x 37 x 2= 456 : 2 =
= 228