E-invoice: 10 practice questions with answers
E-invoice documentation from 1 July 2026, combining amounts on invoices with multiple tax rates, handling incorrect invoices, querying the e-invoice portal and reconciling revenue.
10 questionsabout 15 minutes5 multiple choice · 5 calculationsFor: Invoice preparer, sales accountant, purchase accountant
Machine-translated from the Vietnamese original; under editorial review.
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Which decree on e-invoices and electronic documents takes effect from 1 July 2026?
- A. Decree 252/2026/ND-CP
- B. Decree 254/2026/ND-CP
- C. Decree 253/2026/ND-CP
- D. Decree 255/2026/ND-CP
Show answer and explanation
Answer: B. Decree 254/2026/ND-CP
Decree 254/2026/ND-CP on e-invoices and electronic documents. In the same batch: 252 provides guidance on the Law on Tax Administration, 253 provides guidance on the Law on Personal Income Tax, 255 addresses management of related-party transaction taxes. Invoices issued before 1 July 2026 are read according to the previous layer of documents such as Decree 123/2020/ND-CP — refer to transitional provisions.
Related tool: Tax document library on NganhThue.com
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An e-invoice sent to the buyer is found to have an incorrect unit price. What is the correct handling approach?
- A. Delete the invoice in the software and issue a new one as if nothing happened
- B. Leave it as is and offset it against another invoice at year-end
- C. Issue a new correct invoice and do nothing with the incorrect one
- D. Handle it using an adjustment invoice or replacement invoice in accordance with regulations, with a written agreement between both parties
Show answer and explanation
Answer: D. Handle it using an adjustment invoice or replacement invoice in accordance with regulations, with a written agreement between both parties
An invoice already sent to the tax authority and buyer cannot be deleted like a draft. Errors are handled using an adjustment invoice or replacement invoice; whichever method is chosen and what notification is required must follow the current e-invoice regulations. Issuing an additional invoice while leaving the incorrect one unaddressed means recording revenue twice.
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Suppose an invoice has one line item with a pre-tax price of VND 15 million and a tax rate of 10%. What is the total payment amount shown on the invoice?
Give the answer in VND million.
Show answer and explanation
Answer: VND 16.5 million
Tax amount: 15 × 10% = 1.5 million; total payment: 15 + 1.5 = 16.5 million VND. The three figures — pre-tax price, tax amount, and total payment — must match; a difference of a few dong due to rounding each line is common and depends on how the software rounds.
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Suppose an invoice has two lines (pre-tax price): service D VND 40 million at 10% tax rate; item E VND 6 million at 5% tax rate. What is the total VAT amount?
Give the answer in VND million.
Show answer and explanation
Answer: VND 4.3 million
Calculate by line: 40 × 10% = 4 and 6 × 5% = 0.3; total 4.3 million VND. The VAT return separates revenue and tax by each tax rate, so each line must be assigned the correct rate from the moment the invoice is issued.
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For the same invoice as the previous question (D VND 40 million at 10% tax rate, E VND 6 million at 5% tax rate), what is the total payment amount?
Give the answer in VND million.
Show answer and explanation
Answer: VND 50.3 million
Goods amount: 40 + 6 = 46 million; tax amount: 4.3 million; total payment: 46 + 4.3 = 50.3 million VND. When reconciling with the amount the customer transfers, compare it to this 50.3 million figure, not 46 million.
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An accountant wants to verify whether an input invoice from a supplier has actually been recorded in the tax authority's system. Where should this be checked?
- A. Ask the supplier's business staff
- B. The tax authority's e-invoice portal
- C. Check if the PDF file has a seal image
- D. The supplier's social media page
Show answer and explanation
Answer: B. The tax authority's e-invoice portal
Query the tax authority's e-invoice portal using the information printed on the invoice. A PDF file is only a representation and can be edited; the data on the portal is what the tax authority uses for reconciliation. Many accountants download all input and output invoices from the portal at the end of each month to compare with their records.
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Which Ministry of Finance circular provides guidance on e-invoices and electronic documents in the batch of documents taking effect from 1 July 2026?
- A. Circular 87/2026/TT-BTC
- B. Circular 90/2026/TT-BTC
- C. Circular 94/2026/TT-BTC
- D. Circular 91/2026/TT-BTC
Show answer and explanation
Answer: D. Circular 91/2026/TT-BTC
Circular 91/2026/TT-BTC on e-invoices and electronic documents. In the same batch: 87 provides detailed guidance on personal income tax, 90 addresses tax registration, 94 addresses compliance management and risk management. The content of each provision must be read in the currently effective original text.
Related tool: Tax document library on NganhThue.com
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Suppose in September, sales revenue received in the company's bank account is VND 120 million, but the total output invoices issued (calculated by total payment amount) is VND 100 million. What is the discrepancy that needs to be explained?
Give the answer in VND million.
Show answer and explanation
Answer: VND 20 million
120 − 100 = 20 million VND. The discrepancy is not necessarily an error: it could be advance payment from customers, collection of prior month receivables, or non-revenue amounts such as loan proceeds. However, each item must be identified; sales for which no invoice has been issued must be handled immediately and not left off the books.
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A customer requests: 'No need to issue an invoice, just transfer to the director's personal account for speed.' Which statement is correct?
- A. Acceptable, because the customer is not taking an invoice
- B. Acceptable if the amount is under VND 5 million
- C. Not advisable: sales still require an invoice to be issued and revenue to be recorded; keeping sales revenue off the books carries the risk of back-tax assessment and penalties when the tax authority reconciles cash flows
- D. Acceptable if declared as a lump-sum adjustment at year-end
Show answer and explanation
Answer: C. Not advisable: sales still require an invoice to be issued and revenue to be recorded; keeping sales revenue off the books carries the risk of back-tax assessment and penalties when the tax authority reconciles cash flows
The obligation to issue an invoice is tied to the sale of goods and does not depend on whether the customer takes the invoice. Sales revenue flowing into a personal account is off-book revenue; when the tax authority reconciles cash flows, the enterprise must explain it and may face revenue assessment and back-tax collection.
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Suppose a retail store displays a price including 10% VAT of VND 5.5 million. When issuing an invoice, what is the VAT amount?
Give the answer in VND.
Show answer and explanation
Answer: VND 500,000
Pre-tax price = 5,500,000 ÷ 1.1 = 5,000,000 VND; tax = 5,000,000 × 10% = 500,000 VND. Taking 5.5 million × 10% = 550,000 calculates tax on the tax itself, making the invoice inconsistent with the amount the customer paid.
The questions use rules checked at the time of writing; calculation scenarios are hypothetical with round numbers. Before applying anything to a real filing, read the document in force or ask your managing tax office. TaxDatum.com is run by a private operator and is not a government portal. The Vietnamese original of this set is on HocThue.com.