Description:
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I'm not sure. 100-99.6 the result will return 0.400000001
and i try many case 100 - 99.96 the result still same 0.040000000000006
There return another position of number

Test script:
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echo 100-99.6;
echo "<br>";
echo 100-99.96;
echo "<br>";
echo 1000-999.96;

Expected result:
----------------
0.4
0.04
0.04

Actual result:
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0.40000000000001
0.040000000000006
0.039999999999964