27 Estimate Desk Reasoning Challenges

A. 185

Materials total 90 and labour totals 75; adding delivery of 20 produces 185. The 165 option omits delivery, showing why separate cost lines matter before applying any markup or margin calculation.

Try next: List and subtotal every supplied cost category before pricing.

B. 330

The actual supplied costs add to 330: 120 plus 180 plus 30. Counting the same fixed delivery charge twice would produce 360 and overstate this simplified estimate by 30.

Try next: Assign each fixed charge to one clearly identified line.

C. 4 × 32 + 95 = 223

Four hours must first be converted into a cost using the supplied rate, giving 128. Adding materials of 95 then produces 223; hours and money cannot be directly added as equivalent quantities.

Try next: Write units beside each input before combining values.

A. 20%

Gross margin uses selling price as its denominator, so 60 divided by 300 is 20%. The 25% calculation instead describes markup on cost, making the label—not the subtraction—the error.

Try next: Show the denominator beside every percentage label.

B. 450

For a 20% gross margin, cost represents 80% of price. Dividing 360 by 0.80 gives 450, leaving 90 gross profit, which is exactly 20% of the selling price.

Try next: Verify the chosen price by dividing its gross difference by price.

C. 150 and 33.3%

The discounted price is 450, leaving gross profit of 150. Dividing 150 by 450 gives one-third, or approximately 33.3%; dividing by cost would describe markup rather than gross margin.

Try next: Recalculate both money and percentage measures after a price change.

A. Four boxes costing 96

Three boxes supply only twenty-four pieces, below the twenty-nine required. Four boxes supply thirty-two for 96, leaving three pieces; the purchase must follow whole-box availability rather than an imagined fractional sale.

Try next: Record required quantity separately from purchased quantity and remainder.

B. 30

Two hundred fifty centimetres equal 2.5 metres. Multiplying 2.5 by 12 gives 30; using the raw centimetre number would multiply quantities expressed in incompatible units and inflate the result.

Try next: Convert quantities into the exact unit used by the quoted price.

C. Two packs for 36

Six items require two packs of three. At 18 per pack, the total is 36; six times 18 would purchase eighteen items and misread the supplier's pricing unit in this example.

Try next: Keep package size beside the unit-price field.

A. 650 agreed, with a 90 option pending

The base is agreed, while the additional task remains undecided. Keeping those statuses separate avoids treating the proposal as accepted work or silently including it inside the unchanged base price without support.

Try next: Label optional additions with their actual approval status.

B. Remove disposal and revise the total to 680

Subtracting the declined 140 item gives 680. Removing its description as well ensures that the revised amount corresponds to the revised scope rather than implying that the original work remains included.

Try next: Review scope text and total together after deleting an item.

C. Check the labour effect before finalising the changed estimate

The changed scope may alter more than one cost category, and labour remains an explicit unknown. Verifying that dependency prevents a partial materials calculation from being presented as a complete revised estimate.

Try next: List every affected cost assumption before issuing the revision.

A. 21 higher cost

The unit-price increase is three, applied to seven unchanged units, so cost rises by 21. Estimated cost was 112 and actual cost is 133; the quantity did not change in this case.

Try next: Label the variance by its actual source rather than its appearance.

B. 30

The duration increased by 0.75 hour. Multiplying that difference by 40 gives 30 additional cost; the original 100 labour estimate becomes 130, without any change in the hourly input.

Try next: Preserve planned duration and actual duration on separate review lines.

C. Both quantity and unit price changed; total rose from 100 to 132

The actual quantity and unit price both exceed their estimates. Their combined result is 132 rather than 100, so a useful review identifies both changes instead of assigning the full 32 difference to one unsupported cause.

Try next: Record quantity and unit-price differences before interpreting the total variance.

A. 104 from the second supplier

The first supplier totals 113 after adding delivery to 88. The second totals 104, making it nine lower under the stated equivalence assumption; the item price alone does not settle the comparison.

Try next: Compare complete delivered totals before reviewing non-price differences.

B. Whether preparation and cleanup are included in the second scope

The two totals cannot establish a like-for-like price comparison until their work descriptions are aligned. Missing preparation or cleanup could represent a scope difference rather than a lower price for the same complete job.

Try next: Ask for clarification of the missing work before ranking the totals.

C. Compare the total cost of meeting the actual required quantity

A percentage reduction does not show whether the package is the least costly way to meet the requirement. Comparing necessary quantities and complete totals makes the decision relevant to the job instead of the advertisement's framing.

Try next: Calculate each option against the actual requirement before evaluating the offer.

A. 720

The initial payment reduces the unpaid amount, so 960 minus 240 leaves 720. Adding the payment to the agreed price would confuse money already received with additional work or a new charge.

Try next: Match the payment to the same agreed total before subtracting it.

B. 450

The credit reduces the invoice to 650, and the payment reduces the remaining balance to 450. Both affect the balance, but keeping their different purposes visible makes the record more traceable.

Try next: Retain separate credit and payment entries even when both reduce a balance.

C. Work complete; invoicing and payment status unverified

Completion describes the work, while invoicing and receipt of payment are separate events. The evidence supports completed work only; it cannot establish that a bill was issued or that money arrived.

Try next: Track completion, invoicing and payment with distinct statuses.

A. The exact included quantity

The number of handles determines what the quoted scope includes, and the conversation contains conflicting quantities. Clarifying that count resolves a substantive ambiguity that presentation changes cannot fix for either party.

Try next: Put the agreed quantity directly into the scope description.

B. Fixture allowance 250; selection unresolved

The original line is a stated allowance with an open selection, not unlimited inclusion. Keeping both the amount and unresolved choice visible prevents a summary from silently changing the commercial meaning of the draft.

Try next: Check summaries against the original scope assumptions before sharing them.

C. Clarify and document whether removal is included, excluded or separately priced

Silence has produced conflicting expectations about a concrete task. Explicit clarification aligns the work description with the price, whereas an accurate total alone cannot resolve what that total is intended to cover.

Try next: List the disputed task in the revised scope with its agreed treatment.

A. Historical price awaiting verification

The copied amount is evidence of an earlier price, not current availability or final cost. Labelling its age and verification need keeps the estimate's uncertainty visible instead of treating a stale input as a confirmed purchase.

Try next: Verify the current supplier terms and date the checked input.

B. Reconstructed amount of 60 awaiting confirmation

Subtracting 215 from the stated 275 gives 60, but that is a reconstruction dependent on the total being accurate. It does not independently confirm the missing item's source or validate every line.

Try next: Keep the calculated amount labelled until the original source is found.

C. Arithmetic is checked; the access assumption still needs clarification

Correct arithmetic validates the calculations from supplied inputs, not the completeness of those inputs. The unresolved access condition remains a meaningful assumption and should stay visible until the relevant information is confirmed.

Try next: Resolve the access question or clearly state its provisional treatment.