I'm working on a paired t test step my step. Step 3 requires me to find and

I got (strange looking E with d besides it) and but I havent found (strange E thing with d^2) I've tried to add it all and divide it by the total number (17). I tried to subtract after-before. I tried to times my answer of 123.5 by sum of all d (the stange looking E with d besides it). I have run out of ways to find it. Just to correct , the answer is 1716.9. I dont know how to get this. Helpppp

Here is the data before:

83.3

86.0

82.5

86.7

79.6

87.3

76.9

94.2

73.4

80.5

81.6

83.8

82.1

77.6

83.5

89.9

86.0

and after:

94.3

91.5

91.9

100.3

76.7

98.0

76.8

101.6

94.9

75.2

77.8

95.2

95.5

90.7

92.5

93.8

91.7