Win8 Strawberry 5.30.3.1 (64)  Sun 03/21/2021 13:20:05
C:\@Work\Perl\monks
>perl
printf "decrement: %0.20f \n", 0.01;
for ($x=0.8; $x > 0.1; $x -= 0.01) { printf "%0.20f \n", $x; }
^Z
decrement: 0.01000000000000000021
0.80000000000000004441
0.79000000000000003553
0.78000000000000002665
0.77000000000000001776
0.76000000000000000888
0.75000000000000000000
0.73999999999999999112
0.72999999999999998224
0.71999999999999997335
0.70999999999999996447
0.69999999999999995559
0.68999999999999994671
0.67999999999999993783
0.66999999999999992895
0.65999999999999992006
0.64999999999999991118
0.63999999999999990230
0.62999999999999989342
0.61999999999999988454
0.60999999999999987566
0.59999999999999986677
0.58999999999999985789
0.57999999999999984901
0.56999999999999984013
0.55999999999999983125
0.54999999999999982236
0.53999999999999981348
0.52999999999999980460
0.51999999999999979572
0.50999999999999978684
0.49999999999999977796
0.48999999999999976907
0.47999999999999976019
0.46999999999999975131
0.45999999999999974243
0.44999999999999973355
0.43999999999999972466
0.42999999999999971578
0.41999999999999970690
0.40999999999999969802
0.39999999999999968914
0.38999999999999968026
0.37999999999999967137
0.36999999999999966249
0.35999999999999965361
0.34999999999999964473
0.33999999999999963585
0.32999999999999962697
0.31999999999999961808
0.30999999999999960920
0.29999999999999960032
0.28999999999999959144
0.27999999999999958256
0.26999999999999957367
0.25999999999999956479
0.24999999999999955591
0.23999999999999954703
0.22999999999999953815
0.21999999999999952927
0.20999999999999952038
0.19999999999999951150
0.18999999999999950262
0.17999999999999949374
0.16999999999999948486
0.15999999999999947597
0.14999999999999946709
0.13999999999999945821
0.12999999999999944933
0.11999999999999945433
0.10999999999999945932