(-18-23+20)/3= (-21)/3=-7
21
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23
An=A1+(n-1)d d= 23-18= 5 A1=18A21 = 18+(21-1)*5 = 118
Just over 20 18 + 19 + 21 + 23 = 81 81 / 4 (numbers) = 20.25
62
23
22
(-18-23+20)/3= (-21)/3=-7
21
21
All the numbers are composite except the ones in bold: 18 19 20 21 22 23 24 25.
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to find the mean, you add all the numbers together then divide by how many numbers there are. so the mean for 4 8 18 21 22 23 is 16
23
23