293.3—Simple interest table.

Following is a simple interest table from which computation of interest at 3 per centum per annum on a principal of $1,000 for a fractional 365-day year may be derived by addition only. The interest is stated in the form of a decimal fraction of $1.
Days Interest
1 0821 9178
2 1643 8356
3 2465 7534
4 3287 6712
5 4109 5890
6 4931 5068
7 5753 4246
8 6575 3424
9 7397 2602

Code of Federal Regulations

Example: 3% on $500 for 93 days:
Days
90 $7.3972 602
3 .2465 7534
Interest on $1,000 93 $7.6438 3554
Interest on $500 $3.82