Operations · Original fictional case
Calculate a reorder with reservations and late inbound stock
A buyer needs a replenishment quantity for three items. Work from usable stock at the cutoff, then round the shortage to full supplier packs.
Related work: Production, Planning, and Expediting Clerks · O*NET task 11368.
Your source data
| item | on hand | reserved | inbound units | inbound before cutoff | target | pack |
|---|---|---|---|---|---|---|
| A | 10 | 4 | 5 | yes | 18 | 6 |
| B | 8 | 2 | 20 | no | 12 | 5 |
| C | 20 | 1 | 0 | yes | 12 | 4 |
The rules
- Usable stock = on_hand − reserved + inbound that arrives before the cutoff. Late inbound does not help this order.
- Shortage = max(0, target − usable stock). Purchase complete packs only.
- Round each item separately upward to a pack multiple; do not round the combined shortage.
A method you can reuse
- Calculate A as 10 − 4 + 5 = 11 usable units. Its seven-unit shortage needs two packs of six.
- Exclude B’s 20 inbound units because they miss the cutoff. Six usable units leave a six-unit shortage, needing two packs of five.
- C already has 19 usable units against a target of 12. A nonpositive shortage needs no purchase.
A common wrong turn
Including late inbound makes item B look sufficiently stocked. Availability depends on time as well as quantity.
Use it in a handoff
When extending the sheet, put the cutoff and inbound arrival date in explicit columns, and retain the rounding surplus for the next planning run.
Check your calculation
Enter numbers without currency or percent symbols. A matching result confirms this exercise’s calculation; keep the method in your review note.
See the worked answer
Order item A (units): 12
ceil((18 − 11) / 6) × 6 = 12.
Order item B (units): 10
ceil((12 − 6) / 5) × 5 = 10.
Order item C (units): 0
Usable stock exceeds the target.
Total units ordered: 22
12 + 10 + 0 = 22; the three units of rounding surplus remain in stock.
Source and practice material
Occupational context uses the O*NET® 31.0 Database from the U.S. Department of Labor, Employment and Training Administration, under CC BY 4.0. View the occupation.
Skill Workbench selected and adapted the occupational information and added its own fictional cases, calculations, guidance and worksheets. USDOL/ETA has not approved, endorsed or tested these additions. O*NET® is a trademark of USDOL/ETA.