Bài 1:
a) 4$\frac{5}{9}$ ÷ 2$\frac{5}{18}$ -7
b) (3$\frac{1}{5}$ + 4,5 × 1$\frac{31}{45}$ ÷ (-21$\frac{1}{2}$)
Bài 1: a) 4$\frac{5}{9}$ ÷ 2$\frac{5}{18}$ -7 b) (3$\frac{1}{5}$ + 4,5 × 1$\frac{31}{45}$ ÷ (-21$\frac{1}{2}$)
By Gianna
By Gianna
Bài 1:
a) 4$\frac{5}{9}$ ÷ 2$\frac{5}{18}$ -7
b) (3$\frac{1}{5}$ + 4,5 × 1$\frac{31}{45}$ ÷ (-21$\frac{1}{2}$)
`4 5/9 :2 5/(18)-7`
`=(41)/9 .(18)/(41)-7`
`=2-7`
`=-5`
`3 1/5 +4,5 ×1 (31)/(45) :(-21 1/2)`
`=(16)/5 +9/2 ×(76)/(45)×(-2)/(43)`
`=(16)/5 +(38)/5 .×(-2)/(43)`
`=(16)/5-(76)/(215)`
`=(612)/(215)`
Đáp án:
`a) 4 5/9 : 2 5/18 – 7`
`= 41/9 : 41/18 – 7`
`= 41/9 . 18/41 – 7`
`= 2 – 7`
`= -5`
`b) 3 1/5 + 4,5 × 1 31/45 : (-21 1/2)`
`= 16/5 + 9/2 × 76/45 : -43/2`
`= 16/5 + 38/5 × 2/-43`
`= 16/5 – 76/215`
`= 688/215 -76/215`
`= 612/215`