TÍNH NHANH
A. 3/7 x 5/6 + 5/6 x 4/7
B. 4/9 x 5/6 – 1/3 x 4/9
C. 1/6 : 4/5 + 1/8 : 4/5
D. 1/6 : 4/5 – 1/8 : 4/5
(làm cả bước trung gian hộ mình nha, mình cảm mơn<3)
TÍNH NHANH A. 3/7 x 5/6 + 5/6 x 4/7 B. 4/9 x 5/6 – 1/3 x 4/9 C. 1/6 : 4/5 + 1/8 : 4/5 D. 1/6 : 4/5 – 1/8 : 4/5 (làm cả bước trung gian hộ mình nha,
By Josie
a) 3/7 x 5/6 + 5/6 x 4/7
= 5/6 x ( 3/7 + 4/7 )
= 5/6 x 1
= 5/6
b) 4/9 x 5/6 + 1/3 x 4/9
= 4/9 x ( 5/6 – 1/3 )
= 4/9 x ( 5/6 – 2/6 )
= 4/9 x 3/6
=2/9
c) 1/6 : 4/5 + 1/8 : 4/5
= ( 1/6 + 1/8 ) : 4/5
= ( 4/24 + 3/24 ) x 5/4
= 7/24 x 5/4
= 35/96
d) 1/6 : 4/5 – 1/8 : 4/5
= ( 1/6 – 1/8 ) : 4/5
= ( 4/24 – 3/24) x 5/4
= 1/24 x 5/4
= 5/96
Đáp án:
`A = 5/6`
`B = 2/9`
`C = 35/96`
`D = 5/96`
Giải thích các bước giải:
`A = 3/7 × 5/6 + 5/6 × 4/7`
`A = 5/6 × (3/7 + 4/7)`
`A = 5/6 × 1`
`A = 5/6`
`B = 4/9 × 5/6 – 1/3 × 4/9`
`B = 4/9 × (5/6 – 1/3)`
`B = 4/9 × 1/2`
`B = 2/9`
`C = 1/6 ÷ 4/5 + 1/8 ÷ 4/5`
`C = 1/6 × 5/4 + 1/8 × 5/4`
`C = 5/4 × (1/6 + 1/8)`
`C = 5/4 × 7/24`
`C = 35/96`
`D = 1/6 ÷ 4/5 – 1/8 ÷ 4/5`
`D = 1/6 × 5/4 – 1/8 × 5/4`
`D = 5/4 × (1/6 – 1/8)`
`D = 5/4 × 1/24`
`D = 5/96`
Học tốt. Nocopy