If My Site Helps You,
Please Support It


I've spent about 15,000 hours on this site since 1999—more every day.
Your support is greatly appreciated!
DATE USERS Amazon Donations Book Sales (from my own database; look at rows from that month) TOTAL
MAY 2023 29,315 $0.72 $18.93 $12.92 (1 cat, 1 Alg, 1 SQ Basic2) $32.57
APRIL 2023 28,627 $0.20 $18.93 $10.26 (1 Alg, 1 PreCalcI) $29.39
MARCH 2023 44,394 $2.87 $38.97 (COIL affiliate program payout) $25.07 (2 cat, 2 Alg, 1 AlgSplmt, 1 SQDanceMain) $66.91
FEBRUARY 2023
(began February 4) 		36,998
(new stats: GoatCounter) 		$6.03 $0.00 $22.73 (2 Alg, 1 CalcMain, 1 TeX, 1 Geom) $28.76
DATE USERS Amazon Donations Web Monetization
(began Jan 2021)		 Book Sales (from my own database; look at rows from that month) TOTAL
JANUARY 2023 34,050 $2.65 $0.00 (COIL ended their service) $26.77 (2 Alg, 2 CalcSoln, 1 PreCI, 1 PreCII, 1 TeX) $29.42
DECEMBER 2022 28,183 $2.19 $14.08 $0.00 $386.35 (1 cat, 48 Alg, 1 AlgSplmt, 1 TeX, 1 Geom) $402.62
NOVEMBER 2022 37,850 $6.92 $0.00 $0.00 $66.38 (6 cat, 5 Alg, 1 AlgSplmt, 1 CalcMain) $73.30
OCTOBER 2022 49,858 $2.87 $95.12 (after PayPal fees; was a $100 donation!) $0.00 $7.40 (1 cat, 1 SqDBAS1, 1 Geom) $105.39
SEPTEMBER 2022 65,263 $25.94 $0.00 $0.00 $18.28 (2 cat, 1 alg, 1 alg splmt, 1 TeX) $44.22
AUGUST 2022 unknown $1.69 $0.00 $0.00 $13.35 (1 cat, 1 alg, 1 alg splmt) $15.04
JULY 2022 unknown $6.15 $0.00 $0.00 (I cancelled my COIL subscription) $13.12 (1 cat, 1 calc soln, 1 calc main, 2 TeX) $19.27
JUNE 2022 25,094 $25.94 $0.00 $4.50 COIL (me) $4.00 (1 cat) $34.44
MAY 2022 34,655 $5.64 $0.00 $6.41 COIL (mostly me) $312.45 (3 cat, 31 AlgI, 31 AlgISupl, 1 CalcMain, 1CalcSoln, 2TeX) $324.50
APRIL 2022 37,862 $1.62 $0.00 $2.69 COIL (me) $8.86 (2 cat, 1AlgSupl) $13.17
MARCH 2022 44,814 $1.88 $0.00 $2.99 COIL (me)
(Ray and Julia canceled COIL; affiliate bonuses ended)
 $88.92 (11 Alg, 1 AlgSupl, 2 TeX) $93.79
FEBRUARY 2022 46,724 $3.26 $0.00 $2.17 COIL (me)
$8.66 COIL affiliate bonuses (Ray, Julia)
 $5.25 (1 cat, 1 TeX) $22.95
JANUARY 2022 45,548 $5.08 $0.00 $1.84 COIL (me)
$8.66 COIL affiliate bonuses (Ray, Julia)
 $20.34 (1 cat, 1 Alg, 1AlgSupl, 1 CalcSoln, 1 PreCalcI, 1 PreCalcII, 1 TeX, 1 AlgII) $35.92
DECEMBER 2021 38,126 $19.10 $0.00 $2.10 COIL (me)
$8.66 COIL affiliate bonuses (Ray, Julia)
 $503.93 (1 cat, 62 Alg (Bard Prison Initiative), 1 PreCalcI, 1 TeX, 1 AlgII) $533.79
NOVEMBER 2021 51,838 $11.56 $0.00 $3.45 COIL (mostly me)
$8.66 COIL affiliate bonuses (Ray, Julia)
 $27.74 (3 cat, 2 Alg) $51.41
OCTOBER 2021 68,654 $2.85 $0.00 $5.48 COIL (mostly me)
$8.66 COIL affiliate bonuses (Ray, Julia)
 $24.74 (3 cat, 1 Alg, 1 PreCalcI, 1 PreCalcII) $41.73
SEPTEMBER 2021 77,429 $5.93 $0.00 $5.86 COIL (mostly me)
$8.33 COIL affiliate bonuses (Ray, Julia)
 $26.88 (2 cat, 1 Alg, 2 PreCalcI, 2 PreCalcII, 1 TeX) $47.00
AUGUST 2021 35,390 $8.79 $2.41 $2.68 COIL (mostly me)
$11.73 COIL affiliate bonuses (Ray, Julia, one other)
 $24.90 (2 Alg, 1 Calc main, 1 PreCalcI, 1 PreCalcII, 1 TeX, 1 AlgII) $50.51
JULY 2021 24,298 $8.87 $0.00 $6.24 COIL (most me, $0.98 tip?)
$8.66 COIL affiliate bonuses (Ray, Julia)
$3.00 PayGo (one donation) 		$18.89 (1 Alg, 1 PreCalcI, 1 PreCalcII, 1 Geom, 1 AlgII) $45.66
JUNE 2021 36,375 $5.45 $0.00 $6.44 COIL (about $3.67 from me, $1.88 tips, $0.89 real?)
$11.37 COIL affiliate bonuses (got May + June, they fixed goof)
$0.08 PayGo (only counting third-party, two PreCalc lessons) 		$41.10 (2 cat, 1 Alg, 1 Calc Main, 4 PreCalcI, 2 PreCalcII, 4 TeX, 1 Geom) $64.44
MAY 2021
(blocking code now on all lessons except last half of Precalc) 		62,501 $2.33 $0.00 $12.13 COIL (about $4.16 from me, $7.00 tips, $0.97 real?)
$0.00 COIL affiliate bonuses (Error? They're checking into it.)
 $12.41 (1 cat, 1 Calc Soln, 1 Calc Main, 2 TeX) $26.87
APRIL 2021
(about half of my lessons now have random blocking) 		68,250 $2.70 $9.41 $7.75 COIL (about $6.08 from me/Ray, rest is real?)
$7.10 COIL affiliate bonuses (Ray/Julia)
 $20.14 (2 cat, 1 PreC1, 1 PreC2, 1 TeX, 1 Geom, 1 AlgII) $47.10
MARCH 2021 84,040 $4.06 $4.55 $4.61 COIL (from me)
$12.21 COIL affiliate bonuses
(initial $4.33 goof that COIL gave me; bonuses from husband/daughter subscriptions, nothing from users-at-large)
 $14.51 (2 cat, 3 TeX, 1 Calc main) $39.94
FEBRUARY 2021 86,735 $7.88 $0
(stopped Ko-fi; was causing a page error) 		$33.21 (about $4 came from me; there were several ‘sudden’ unexplained payments—perhaps an incentive program?) $14.56 (2 cat, 2 TeX, 1 AlgWeb1, 1 AlgWeb2) $55.65
JANUARY 2021 82,470
(GA now on most pgs) 		$10.05 $5.53
(from Ko-fi) 		$4.07 (most from me) $35.13 (3 cat, 2 Alg1, 1 CalcSoln, 1 PreCalc1, 1 PreCalc2, 2 TeX, 1 Geom, 1 AlgII) $54.78
DECEMBER 2020 65,400
(GA not on all pgs) 		$22.63 $15.97
(includes Ko-fi) 		NA $8.00 (2 cat) $46.60
NOVEMBER 2020 67,281
(GA not on all pgs) 		$8.68 $0 NA $8.72 (1 CalcSoln, 5 TeX) $17.40
OCTOBER 2020 109,618
(GA not on all pgs) 		$3.04 $0 NA $20.61 (1 cat, 1 Alg1, 1 CalcSoln, 1 CalcMain, 1 Alg1Web#2) $23.65
SEPTEMBER 2020 92,250
(GA not on all pgs) 		$4.75 $0 NA $19.89 (2 Alg1, 1 CalcMain) $24.64
AUGUST 2020 38,716
(GA not on all pgs) 		$8.24 $0 NA $22.03 (4 cat, 1 Alg1, 1 CalcMain) $29.95
JULY 2020 25,643
(GA not on all pgs) 		$14.33 $0 NA $15.62 (1 cat, 1 Alg1, 3 TeX) $29.95
JUNE 2020 29,825
(GA not on all pgs) 		$1.94 $0 NA $15.56 (4 cat, 1 AlgII, 1 TeX) $17.50
MAY 2020 44,500
(GA not on all pgs) 		$4.22 $0 NA $27.26 (4 cat, 1 alg, 1 calc, 1 calc soln, 2 TeX) $31.48


DATE # UNIQUE MONTHLY VISITORS ADS Amazon donations + digital commerce
(less PayPal fees and SendOwl)		 Book Sales
(began June 2018)		 TOTAL
APRIL 2020 Server stopped AWStats $0 $0.50 $0 $6.16
(1 TeX $1.22
2 CalcSoln $4.94)		 $6.66
MARCH 2020 Server stopped AWStats $0 $3.19 $0 $16.80
(1 Alg: $7.87
1 AlgII $2.31
1 Calc $4.15
1 CalcSoln $2.47)		 $19.99
FEBRUARY 2020 51,684 $0 $2.74 $0 $20.26
(1 algebra: $7.87
2 Mainstream SQ: $1.54)
1 PreC1 $2.39
1 PreC2 $2.48
1 Geom $1.92
1 AlgWeb1 $1.94
1 AlgWeb2 $2.12)		 $23.00
JANUARY 2020 43,838 $0 $4.59 $0 $22.18
(3 cat: $12.00
1 algebra: $7.87
3 Mainstream SQ: $2.31)		 $26.77
DECEMBER 2019 32,964 $0 $32.08 $0 $12.92
(1 cat: $4.00
1 algebra: $7.87
1 SQ Bas2: $1.05)		 $45.00
NOVEMBER 2019 41,218 $0 $16.63 $0 $15.95
(2 algebra: $11.30
1 calc: $4.15
1 calc soln: $0.50)		 $32.58
OCTOBER 2019 55,640 $1.63 (removed AdSense on 10/3/19) $3.63 $0 $7.37
(1 cat: $4.00
1 algWeb2: $2.12
1 MathJax: $1.25)		 $12.63
SEPTEMBER 2019 51,976 $11.11 $19.17 $0 $64.68
(8 cat: $31.23
1 alg: $5.52
1 algWeb1: $1.94
2 geom: $3.84
2 alg2: $4.62
1 precalc1: $2.39
3 precalc2: $7.44
1 calc: $4.15
1 SDB2: $1.05
3 MathJax: $2.50)		 $94.96
AUGUST 2019 31,992 $6.28 $14.84 $0 $110.07
(22 cat: $88.00
2 algebra: $15.74
2 precalc1: $2.78
1 SDB2: $1.05
2 MathJax: $2.50)		 $131.19
JULY 2019 21,588 $6.19 $30.18 $0 $55.74
(10 cat: $40.00
2 algebra: $15.74)		 $92.11
JUNE 2019 29,666 $6.21 $18.31 $0 $4.00
(1 original cat book)		 $28.52
MAY 2019 50,179 $9.47 $9.62 $0 $48.28
(3 cat: $12.00
3 algebra: $23.61
1 calc soln: $1.68
3 calc main: $10.99)		 $67.37
APRIL 2019 53,400 $16.10 $12.08 $0 $12.94
(2 cat: $8.00
2 calc soln: $4.94)		 $41.12
MARCH 2019 57,282 $15.34 $43.16 $3.52 (last recurring donation) $10.62
(1 cat: $4.00
1 calculus: $4.15
1 calc soln: $2.47)		 $72.64
FEBRUARY 2019 48,374 $16.52 $11.97 $3.52 $15.74
(2 algebra: $15.74)		 $47.75
JANUARY 2019 50,606 $16.11 $13.58 $3.52 $27.83
(1 algebra: $7.87
2 cat: $5.77
4 calculus: $11.72
1 calc soln: $2.47)		 $61.04
DECEMBER 2018 43,169 $14.23 $13.54 $3.52 $40.97
(2 algebra: $15.74
3 cat: $12.00
2 calculus: $8.29
2 calc soln: $4.94)		 $72.26
NOVEMBER 2018 52,457 $17.25 $7.69 $3.52 + $0 - $0 = $3.52
(removed digital products, cancelled SendOwl)		 $7.87 + $8.00 + $2.47 = $18.34
(1 algebra: $7.87
2 cat: $8.00
1 calculus soln manual: $2.47)		 $46.80
OCTOBER 2018 71,823 $16.46 $30.46 $3.52 + $3.64 - $9.00 = -$1.84 $7.87 + $8.00 = $15.87
(1 algebra: $7.87
2 cat: $8.00)		 $60.95
SEPTEMBER 2018 84,073 $26.61 $20.28 $3.52 + $20.46 - $9.00 = $14.98 $15.74 + $8.00 = $23.74
(2 algebra: $15.74
2 cat: $8.00)		 $85.61
AUGUST 2018 50,853 $15.71 $13.33 $3.52 + $9.41 - $9.00 = $3.93 $15.74
(2 algebra: $15.74
0 cat: $0.00)		 $48.71
JULY 2018 41,252 $11.83 $12.65 $3.52 + $18.21 - $9.00 = $12.73
(switched SendOwl plan)		 $25.26
(3 algebra: $21.26
1 cat: $4.00)		 $62.47
JUNE 2018 50,534 $14.23 $22.01 $37.72 - $24.00 = $13.72
(includes 1st month of digital sales;
SendOwl costs $24/month)		 $67.74
(2 algebra: $15.74
13 cat: $52.00)		 $117.70
MAY 2018 59,310 $18.23 $20.28 $3.52   $42.03
APRIL 2018 55,248 $16.96 $23.98 $8.07   $49.01
MARCH 2018 61,125 $19.27 $36.92 $3.52   $59.71
FEBRUARY 2018 81,069 $28.53 $9.80 $3.52   $41.85
JANUARY 2018 80,552 $14.82 $31.79 $3.52   $50.13
DECEMBER 2017 64,221 $14.66 $42.50 $3.52   $60.68
NOVEMBER 2017 79,329 $20.33 $21.17 $3.52   $45.02
OCTOBER 2017 104,131 $20.58 $32.95 $3.52   $57.05
SEPTEMBER 2017 107,576 $27.46 $16.56 $0.00   $44.02
AUGUST 2017 69,164 $10.09 $20.27 $0.00   $30.36
JULY 2017 46,801 $4.98 $55.24 $0.00   $60.22
JUNE 2017 53,814 $6.39 $33.96 $0.00   $40.35
MAY 2017 63,250 $7.96 $30.11 $0.00   $38.07
APRIL 2017 62,587 $6.90 $34.07 $0.00   $40.97
MARCH 2017 73,284 $7.59 $12.43 $0.00   $20.02
FEBRUARY 2017 74,188 $7.35 $20.14 $0.00   $27.49
JANUARY 2017 68,879 $5.51 $14.11 $9.41   $29.03
DECEMBER 2016 48,690 $8.48 $19.38 $23.97   $51.83
NOVEMBER 2016 57,339 $10.81 $42.89 $0.00   $53.70
OCTOBER 2016 72,067 $12.52 $30.39 $0.00   $42.91
SEPTEMBER 2016 77,426 $12.28 $27.70 $0.00   $39.98
AUGUST 2016 45,074 $9.79 $17.35 $23.97   $51.11
JULY 2016 24,268 $6.10 $38.05 $0.00   $44.15
JUNE 2016 28,693 $5.83 $41.21 $0.00   $47.04
MAY 2016 28,466 $4.64 $37.62 $0.00   $42.26
APRIL 2016 30,172 $4.01
(tiny ads only) 		$18.10 $0.00   $22.11
MARCH 2016 33,206 $16.33
(I took all ads off on March 25, 2016)
(I put small ads back on, on April 5, 2016) 		$38.94 $0.00   $55.27
FEBRUARY 2016 37,867 $27.70 $15.71 $11.35   $54.76
JANUARY 2016 36,529 $37.08 $16.62 $0.00   $53.70
DECEMBER 2015 27,282 $21.35 $15.15 $0.00   $36.50
NOVEMBER 2015 35,074 $28.33 $20.03 $0.00   $48.36
OCTOBER 2015 46,704 $55.81 $40.85 $0.00   $96.66
SEPTEMBER 2015 55,907 $52.25 $24.73 $0.00   $76.98
AUGUST 2015 31,472 $33.41 $14.54 $0.00   $47.95
JULY 2015 18,499 $13.13 $18.16 $11.35   $42.64
JUNE 2015 25,842 $24.65 $22.24 $4.55   $51.44
MAY 2015 24,954 $20.55 $12.78 $0.00   $33.33
APRIL 2015 24,409 $15.15 $28.57 $0.00   $43.72
MARCH 2015 23,901 $23.82 $29.40 $14.11   $67.33
FEBRUARY 2015 28,139 $28.46 $22.39 $9.41   $60.26
JANUARY 2015 28,754 $28.82 $22.24 $0.00   $51.06
DECEMBER 2014 24,784 $30.54 $19.01 $0.00   $49.55
NOVEMBER 2014 31,391 $27.50 $28.63 $145.05
(My two largest donations to date!
$100 and $50 on the same day!) 		  $201.18
OCTOBER 2014 40,024 $40.93 $25.24 $0.00   $66.17
SEPTEMBER 2014 44,716 $53.41 $10.69 $0.00   $64.10
AUGUST 2014 29,357 $22.00 $31.29 $0.00   $53.29
JULY 2014 22,096 $23.05 $23.60 $23.97
(My largest donation ever! $25) 		  $70.62
JUNE 2014 29,931 $22.86 $57.17 $0.00   $80.03
MAY 2014 22,013 $16.83 $22.91 $0.00   $39.74
APRIL 2014 16,027 $15.21 $35.15 $0.00   $50.36
MARCH 2014 17,502 $26.46 $11.75 $0.00   $38.21
FEBRUARY 2014 18,580 $27.64 $9.64 $0.00   $37.28
JANUARY 2014 19,920 $26.25 $2.52 $0.00   $28.77
DECEMBER 2013 16,623 $27.81 $13.11 $0.00   $40.92
NOVEMBER 2013 17,838 (updated to MathJax 2.2, then 2.3) $27.31 $3.51 $0.00   $30.82
OCTOBER 2013 25,317 $31.60 $18.07 $0.00   $49.67
SEPTEMBER 2013 28,401 $26.71 $13.21 $0.00   $39.92
AUGUST 2013 17,722 (my failed experiment with removing ads) $3.91 $20.66 $0.00   $24.57
JULY 2013 14,905 $32.83 $20.87 $0.67   $54.37
JUNE 2013 20,367 $49.42 $7.38 $0.00   $56.80
MAY 2013 28,202 $66.92 $16.75 $0.00   $83.67
APRIL 2013 38,791 $82.53 $9.50 $0.00   $92.03
MARCH 2013 47,324 $117.84 $12.86 $38.61   $169.31
FEBRUARY 2013 56,083 $134.88 $4.15 $9.41   $148.44
JANUARY 2013 69,763 $182.81 $31.33 $0.00   $214.14
DECEMBER 2012 55,269 $150.84 $15.55 $6.00   $172.39
NOVEMBER 2012 69,896 $122.23 $13.99 $1.00   $137.22
OCTOBER 2012 106,990 $180.88 $15.30 $0   $196.18
SEPTEMBER 2012 121,176 $207.90 $12.96 $5.10   $225.96
AUGUST 2012 72,114 $79.16 $3.44 $0   $82.60
JULY 2012 53,041 $58.53 $36.89 $0   $95.42
JUNE 2012 71,153 $77.93 $45.89 $0   $123.82
MAY 2012 87,241 $87.45 $21.77 $0   $109.22
APR 2012 79,644 $86.49 $1.48 $0   $87.97
MAR 2012 79,981 $85.47 $2.00 $0   $87.47
FEB 2012 71,616 $108.38 $1.71 $0   $110.09
JAN 2012 77,939 $108.66 $20.49 $0   $129.15