The learning archive · 2022–2023
Early notebooks.
Try small programs from my early repositories and inspect their revised calculations.
LoanCalculator
Revisited in 2026| Month | Payment | Principal | Interest | Balance |
|---|---|---|---|---|
| 1 | $269.53 | $232.03 | $37.50 | $14,767.97 |
| 2 | $269.53 | $232.61 | $36.92 | $14,535.36 |
| 3 | $269.53 | $233.19 | $36.34 | $14,302.17 |
| 4 | $269.53 | $233.77 | $35.76 | $14,068.40 |
| 5 | $269.53 | $234.36 | $35.17 | $13,834.04 |
| 6 | $269.53 | $234.94 | $34.59 | $13,599.10 |
| 7 | $269.53 | $235.53 | $34.00 | $13,363.57 |
| 8 | $269.53 | $236.12 | $33.41 | $13,127.45 |
| 9 | $269.53 | $236.71 | $32.82 | $12,890.74 |
| 10 | $269.53 | $237.30 | $32.23 | $12,653.44 |
| 11 | $269.53 | $237.90 | $31.63 | $12,415.54 |
| 12 | $269.53 | $238.49 | $31.04 | $12,177.05 |
| 13 | $269.53 | $239.09 | $30.44 | $11,937.96 |
| 14 | $269.53 | $239.69 | $29.84 | $11,698.27 |
| 15 | $269.53 | $240.28 | $29.25 | $11,457.99 |
| 16 | $269.53 | $240.89 | $28.64 | $11,217.10 |
| 17 | $269.53 | $241.49 | $28.04 | $10,975.61 |
| 18 | $269.53 | $242.09 | $27.44 | $10,733.52 |
| 19 | $269.53 | $242.70 | $26.83 | $10,490.82 |
| 20 | $269.53 | $243.30 | $26.23 | $10,247.52 |
| 21 | $269.53 | $243.91 | $25.62 | $10,003.61 |
| 22 | $269.53 | $244.52 | $25.01 | $9,759.09 |
| 23 | $269.53 | $245.13 | $24.40 | $9,513.96 |
| 24 | $269.53 | $245.75 | $23.78 | $9,268.21 |
| 25 | $269.53 | $246.36 | $23.17 | $9,021.85 |
| 26 | $269.53 | $246.98 | $22.55 | $8,774.87 |
| 27 | $269.53 | $247.59 | $21.94 | $8,527.28 |
| 28 | $269.53 | $248.21 | $21.32 | $8,279.07 |
| 29 | $269.53 | $248.83 | $20.70 | $8,030.24 |
| 30 | $269.53 | $249.45 | $20.08 | $7,780.79 |
| 31 | $269.53 | $250.08 | $19.45 | $7,530.71 |
| 32 | $269.53 | $250.70 | $18.83 | $7,280.01 |
| 33 | $269.53 | $251.33 | $18.20 | $7,028.68 |
| 34 | $269.53 | $251.96 | $17.57 | $6,776.72 |
| 35 | $269.53 | $252.59 | $16.94 | $6,524.13 |
| 36 | $269.53 | $253.22 | $16.31 | $6,270.91 |
| 37 | $269.53 | $253.85 | $15.68 | $6,017.06 |
| 38 | $269.53 | $254.49 | $15.04 | $5,762.57 |
| 39 | $269.53 | $255.12 | $14.41 | $5,507.45 |
| 40 | $269.53 | $255.76 | $13.77 | $5,251.69 |
| 41 | $269.53 | $256.40 | $13.13 | $4,995.29 |
| 42 | $269.53 | $257.04 | $12.49 | $4,738.25 |
| 43 | $269.53 | $257.68 | $11.85 | $4,480.57 |
| 44 | $269.53 | $258.33 | $11.20 | $4,222.24 |
| 45 | $269.53 | $258.97 | $10.56 | $3,963.27 |
| 46 | $269.53 | $259.62 | $9.91 | $3,703.65 |
| 47 | $269.53 | $260.27 | $9.26 | $3,443.38 |
| 48 | $269.53 | $260.92 | $8.61 | $3,182.46 |
| 49 | $269.53 | $261.57 | $7.96 | $2,920.89 |
| 50 | $269.53 | $262.23 | $7.30 | $2,658.66 |
| 51 | $269.53 | $262.88 | $6.65 | $2,395.78 |
| 52 | $269.53 | $263.54 | $5.99 | $2,132.24 |
| 53 | $269.53 | $264.20 | $5.33 | $1,868.04 |
| 54 | $269.53 | $264.86 | $4.67 | $1,603.18 |
| 55 | $269.53 | $265.52 | $4.01 | $1,337.66 |
| 56 | $269.53 | $266.19 | $3.34 | $1,071.47 |
| 57 | $269.53 | $266.85 | $2.68 | $804.62 |
| 58 | $269.53 | $267.52 | $2.01 | $537.10 |
| 59 | $269.53 | $268.19 | $1.34 | $268.91 |
| 60 | $269.58 | $268.91 | $0.67 | $0.00 |
| Total | $16,171.85 | $15,000.00 | $1,171.85 | $0.00 |
Then
The original formula divided by zero at 0% and used absolute values to hide a negative remaining balance.
Now
Integer-cent accounting, explicit monthly rounding, a separate 0% allocation, and an exact final payoff.
The original repositories stay intact. These local editions make the assumptions visible and the edge cases testable.
The person behind the project
A note from Luis.
These early programs belong in the story too. Revisiting them makes the growth visible: clearer inputs, explicit limits, and calculations that can be checked. The original repositories remain linked beside the revised examples.
Who it helps
Visitors who want to see the fundamentals behind my current work.
Try this
Change a sample loan input, calculate its schedule, and inspect how the final payment brings the balance to zero.
See the professional work that followed