解(1)20-9.18-0.82,
=20-(9.18+0.82),
=20-10,
=10.
(2)6.53-(1.53+2.6),
=6.53-1.53-2.6,
=4-2.6,
=1.4.
(3)5.52-1.074-0.926,
=5.52-(1.074+0.926),
=5.52-2,
=3.52.
(4)4.21+1.04+0.79,
=4.21+0.79+1.04,
=5+1.04,
=6.04.
解(1)20-9.18-0.82,
=20-(9.18+0.82),
=20-10,
=10.
(2)6.53-(1.53+2.6),
=6.53-1.53-2.6,
=4-2.6,
=1.4.
(3)5.52-1.074-0.926,
=5.52-(1.074+0.926),
=5.52-2,
=3.52.
(4)4.21+1.04+0.79,
=4.21+0.79+1.04,
=5+1.04,
=6.04.