Integer value range: from -32768 to 32767; Single value range: negative number -3.402823E+38 to-1.401298e-45; Positive number 1.405438+0298e-45 to 3.402823E38. There are only 7 significant digits. Double: The range of numbers that can be represented is the number whose absolute value is less than 10 308, with 15 significant digits. For example, 1.23456789D+ 12 is a double-precision real number, that is,1.23456789×1012.