![](https://rs.olm.vn/images/avt/0.png?1311)
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)
a) \(67\cdot99\)
\(=67\cdot\left(100-1\right)\)
\(=6700-67\)
\(=6633\)
b) \(998\cdot34\)
\(=\left(1000-2\right)\cdot34\)
\(=34000-68\)
\(=33932\)
a, 67 x 99= 67 x 100 - 67 = 6700 - 67= 6633
b, 998 x 34= 1000 x 34 - 34 x 2= 34000 - 68 = 33932
![](https://rs.olm.vn/images/avt/0.png?1311)
a, - 128 . (-25+89) + 128.(89-125)
= 128 . - (-25 +89) + 128 . (89 - 125)
= 128 . [-(-25+89)+(89 - 125)]
= 128. (25+89+89-125)
= 128 . (89.2+-100)=128.78=(120+8).(70+8)= 8.190=1520
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 4 7 + 3 4 + 2 7 + 5 4 + 1 7 = 4 7 + 2 7 + 1 7 + 3 4 + 5 4 = 3
b) − 5 7 + 3 4 + − 1 5 + − 2 7 + 1 4 = − 5 7 + − 2 7 + 3 4 + 1 4 + − 1 5 = − 1 + 1 + − 1 5 = − 1 5
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a, 12 . 125 . 54
=4*3*25*5*2*27
=(25*4)*(5*2)*(27*3)
=100*81*10
=81*1000
=81000
a, 12 . 125 . 54
= ( 125 . 4 . 2 ) . 3 . 27
= 1000 . 81
= 81000
b, 998 . 34
= ( 1000 - 2 ) . 34
= 1000 . 34 - 2 . 34
= 34000 - 68
= 33923