Start from a clear retail basket
One selected Grenade single,one selected Fulfil single and one TREK3-pack total£9.40 ordinary merchandise. That buys five declared bars,not three. The ledger starts with complete retail offers and whole offer quantities. If the actual selected Fulfil membership price applies,enter the confirmed ticket and recalculate rather than applying an assumed additional discount to an already reduced price.
Exact full credit reaches zero
A confirmed merchandise-only credit of£9.40 against£9.40 leaves£0 merchandise payable. In a hypothetical arithmetic test,delivery£4.99 and additional tax£1.25 remain as£6.24 payable charges. Those are test inputs,not actual grocery fees. A credit on the bars must not silently erase shipping or duplicate VAT already included in the consumer ticket.
One penny over is rejected
A£9.41 credit against the£9.40 base is unresolved rather than creating a negative bill. Blank or negative prices,exponent notation,fractions of a penny and values outside the supported range are rejected. Quantities must be whole nonnegative numbers. Blank charge fields prevent a final total instead of being assumed zero.
Use meaningful decimal checks
The tool uses integer pence for purchase arithmetic. Tests include£47.99 ×2 =£95.98 and£0.10 ×3 =£0.30,with exact full credits leaving zero merchandise. Maximum supported inputs are tested within safe integer bounds. Rounded per-bar or per100g displays remain distinct from the integer-pence basket total.
Keep the tool within its role
The ledger does not calculate personal protein need,medical diets,consumption frequency or sports outcomes. It does not place orders,log in to loyalty accounts,reserve stock or confirm merchant approval. Actual received labels,local checkout and independent food/nutrition/content review remain pending. It provides a transparent purchase calculation while leaving unsupported nutrient and personal-suitability questions unresolved.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or retailer instructions. Current received labels and independent food/nutrition/content/commerce review remain pending.
Tesco UK Grenade OREO60g313750416 ↗
Tesco UK Fulfil Chocolate Salted Caramel55g330762768 ↗