Description:
------------
Just calculations. At the end of them unexpected result

Test script:
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$total_vote = 2.9; 
$points_teaches = [-0.1, -0.1, -0.1, -0.1, -0.1, -0.1, -0.1, -0.1, -0.1, -0.1];
foreach($points_teaches as $point) { 
$total_vote += $point; 
} 
$total_vote += -0.3; 
$total_vote += -0.3; 
$total_vote += -0.3; 
$total_vote += -0.5; 
$points_p = [-0.05, -0.05, -0.05, -0.05, -0.05 -0.05, -0.05, -0.05, -0.05, -0.05]; 
$p = 0.0; 
foreach ($points_p as $points) { 
$p += $points; 
} 
$total_vote += $p; 
die($total_vote);

Expected result:
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$total_vote == 0

Actual result:
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$total_vote == -1.1102230246252E-15