Question 26
EasyOriginal questionA shop gives each product a 5-digit code. The first four digits name the product, and the fifth, the check digit, is the sum of the first four digits taken modulo 10.
What is the check digit for a product whose first four digits are 4728?
Show the answer and explanation
CorrectNot quiteAnswer A
Correct answer: A
Explanation
.
.
Worth noting
21 is the sum itself; a single digit is needed, its remainder by 10.
- Concept
- Computing a check digit
- Typical timeTypical
- 90 s
- Your timeYours
- —
Practise this chapter →
Ten questions from Modulo Arithmetic & Congruence, at your own pace.