The range is 30. To find the range, you subtract the largest number, which is 100, by the smallest number, which is 70.
S = 1 + 3 + 5 + ... + 11 + 13 + 15
S = 15 + 13 + 11 + ... + 5 + 3 + 1
==> 2S = (1 + 15) + (3 + 13) + (5 + 11) + ... + (15 + 1)
There are 8 terms in the sum, so
2S = 8 * 16 = 128
S = 128/2 = 64
Number 5 is 22 and 35
For example: 7+1=8, 8+2 =10, 10+3=13, 13+4=17, 17+5=22, 22+6=28, 28+7=35
1st and 2nd pictures are for finding area and 3rd picture is for finding perimeter
hope you understood well and if not and you can ask again