You're effectively saying 'what is 13.1 - 10.9' therefore the answer is 2.2
Gunpartscorp.com has them 15.00 plus shipping clips fit models 52 56 57 69 69a 75 also can be found on ebay I found them at brownells.com for $10.50, each.
23 + 56 - 4 = 75
Mean = 61.857142... Median = 57 Mode = 56 Range = 27
65
21 + 42 + 52 + 58 + 72 + 75 + 89 = 409
57
50, 51, 52, 54, 55, 56, 57, 59, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76
90 minus 75 =15 therefore 15 + 75 = 90
mean: 60 median: 56.5 mode: 56 range: [48,75]
Mean: 60 Median: 56.5 Mode: 56 Range: 28
75% of 52 = 75% * 52 = 0.75 * 52 = 39
mean = (65 + 56 + 57 + 75 + 76 + 66 + 64)/7 = 65.57 median = "middle" number = 65 mode = most common number = all are equally common