I have a couple of PHP programs that don’t seem to add properly. The first one is a credit card number string and I’m adding each number to calculate the check digit. The second is a hotel reservation and calculates the total cost of a stay for each of 4 rooms. I get an extra ‘1’ added to the sum as it goes through the calculation. Here is the example of the Room Rates:

<?php
//\$GTotal1 = 2507; This is the value for room 1
//\$GTotal2 = 0; room 2 value
//\$GTotal3 = 0; room 3 value
//\$GTotal4 = 0; room 4 value
// \$GTotalx = (\$GTotal1 + \$GTotal2 + \$GTotal3 + \$GTotal4);
\$GTotalx = \$GTotal1; // add room 1 total GTotalx now 2507
\$GTotalx += \$GTotal2; // room 2 total GTotalx now 2508
\$GTotalx += \$GTotal3; // room 3 total GTotalx now 2508
\$GTotalx += \$GTotal4; // room 4 total GTotalx now 2509
echo \$GTotalx;
?>

Notice that the values for rooms 1-4 are 2507, 0, 0 and 0 entering this code or I can hard code it as commented out. Add this up and PHP gives me 2509. If I do it all on one line as commented out I still get 2509. One time it actually calculated correctly. HELP???

I’m new but this doesn’t make sense.