Đáp án_Giải thích các bước giải:
Bài 1:
`1 1/2+1 1/4=3/2+5/4=6/4+5/4=11/4`
`1 1/2-1 1/4=3/2-5/4=6/4-5/4=1/4`
`1 1/2×1 1/4=3/2×5/4=15/8`
`1 1/2:1 1/4=3/2:5/4=3/2×4/5=(3×2)/5=6/5`
Bài 2:
`a)` `3 3/4+1 1/2=15/4+3/2=15/4+6/4=21/4`
`b)` `3 3/4-1 1/2=15/4-3/2=15/4-6/4=9/4`
`c)` `3 3/4×1 1/2=15/4×3/2=45/8`
`d)` `3 3/4:1 1/2=15/4:3/2=15/4*2/3=5/2`
Bài 3:
`a)` `1 1/2×1 1/3×1 1/4`
`=3/2×4/3×5/4`
`=(3×4×5)/(2×3×4)`
`=5/2`
`b)` `1 1/2:1 1/3:1 1/4`
`=3/2:4/3:5/4`
`=3/2×3/4×4/5`
`=(3×3×4)/(2×4×5)`
`=(3×3)/(2×5)`
`=9/10`
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