[(-4)-(+7)]-(-5)
=(-4-7)+5
=-11+5
=-6
2. 3-[(-3)-(+12)]
=3-(-3-12)
=3-(-15)
=3+15
=18
3. 數(shù)軸上a與b兩點(diǎn)表示的有理數(shù)分別是負(fù)六右二分之一和七右四分之三,求兩點(diǎn)間的距離
(7+3/4)-[-(6+1/2)]
=7+3/4+6+1/2
=13+3/4+2/4
=13+5/4
=14+1/4
兩點(diǎn)間的距離:14又4分之1
[(-4)-(+7)]-(-5)
=(-4-7)+5
=-11+5
=-6
2. 3-[(-3)-(+12)]
=3-(-3-12)
=3-(-15)
=3+15
=18
3. 數(shù)軸上a與b兩點(diǎn)表示的有理數(shù)分別是負(fù)六右二分之一和七右四分之三,求兩點(diǎn)間的距離
(7+3/4)-[-(6+1/2)]
=7+3/4+6+1/2
=13+3/4+2/4
=13+5/4
=14+1/4
兩點(diǎn)間的距離:14又4分之1