We create a table with a field in type of numeric(18,2)

In case of isql, I get the correct result, but in case of PHP, the result is strange

create table test
(
    Id                varchar(32)            not null,
    AA                numeric(18,2)          not null,
    constraint PK_ID primary key (Id)
)
go

INSERT INTO test (Id, AA) VALUES ('0001', 80)
INSERT INTO test (Id, AA) VALUES ('0002', 80.00)
INSERT INTO test (Id, AA) VALUES ('0003', 80.01)
INSERT INTO test (Id, AA) VALUES ('0004', 80.5)
INSERT INTO test (Id, AA) VALUES ('0005', 80.50)
INSERT INTO test (Id, AA) VALUES ('0006', 80.51)
INSERT INTO test (Id, AA) VALUES ('0007', 1111111111111111.55)
INSERT INTO test (Id, AA) VALUES ('0008', 1111111111111111.50)
go

My test script is:

<?php
@$results	= sybase_query("select * from test");

while ($row		= sybase_fetch_array($results)){
	echo "$row[0] ||$row[1] <br>";
}	
?>		

But I get the following results:

0001 ||80.0 
0002 ||80.0 
0003 ||80.010000000000005 
0004 ||80.5 
0005 ||80.5 
0006 ||80.510000000000005 
0007 ||1111111111111111.5 
0008 ||1111111111111111.5