Tính bằng hai cách A,(2/3*4/5)*5/6. B,(1/2+1/3)*1/5 07/11/2021 Bởi Eden Tính bằng hai cách A,(2/3*4/5)*5/6. B,(1/2+1/3)*1/5
C1: `(2/3×4/5)×5/6=8/15×5/6=(8×5)/(15×6)=(2×2×2×5)/(3×5×2×3)=4/9` C2: `(2/3×4/5)×5/6=2/3×(4/5 ×5/6)=2/3×4/6=(2×4)/(3×6)=(2×4)/(3×2×3)=4/9` C1: `(1/2+1/3)×1/5=((3+2)/6)×1/5=5/6×1/5=1/6` C2: `(1/2+1/3)×1/5=1/2×1/5+1/3×1/5=1/10+1/15=3/30+2/30=5/30=1/6` Bình luận
Đáp án: phuonganhthnm5b C1 : a. ( 2/3 x 4/5 ) x 5/6 C2 : a. ( 2/3 x 4/5 ) x 5/6 = 8/15 x 5/6 = ( 2/3 x 5/6 ) x 4/5 = 4/9 = 5/9 x 4/5 = 4/9 Bình luận
C1:
`(2/3×4/5)×5/6=8/15×5/6=(8×5)/(15×6)=(2×2×2×5)/(3×5×2×3)=4/9`
C2:
`(2/3×4/5)×5/6=2/3×(4/5 ×5/6)=2/3×4/6=(2×4)/(3×6)=(2×4)/(3×2×3)=4/9`
C1:
`(1/2+1/3)×1/5=((3+2)/6)×1/5=5/6×1/5=1/6`
C2:
`(1/2+1/3)×1/5=1/2×1/5+1/3×1/5=1/10+1/15=3/30+2/30=5/30=1/6`
Đáp án:
C1 : a. ( 2/3 x 4/5 ) x 5/6 C2 : a. ( 2/3 x 4/5 ) x 5/6
= 8/15 x 5/6 = ( 2/3 x 5/6 ) x 4/5
= 4/9 = 5/9 x 4/5
= 4/9