(1)(
2
5 +
1
8 )÷3
=(
16
40 +
5
40 )÷3,
=
21
40 ÷3,
=
21
40 ×
1
3
=
7
40 .
答:这个数为
7
40 .
(2)12*3,
=12×
1
3 -3,
=4-3,
=1.
答:根据此规定:12*3等于1.
(1)(
2
5 +
1
8 )÷3
=(
16
40 +
5
40 )÷3,
=
21
40 ÷3,
=
21
40 ×
1
3
=
7
40 .
答:这个数为
7
40 .
(2)12*3,
=12×
1
3 -3,
=4-3,
=1.
答:根据此规定:12*3等于1.