Direct proof Quiz
10 questions · easy to harder · Discrete Math · score and step-by-step answers
How it works
- 10 questions, about 30 minutes (a timer counts down; you can hide it). Solve it right here: no sign-up.
- 0 questions have choices. For the others you type the answer: a number like 4, −2, 7/2 or 3.5, or for example x = 4, x = 2 or x = −3, (3, 5), 2x + 1. Use ^ for powers (x^2) and sqrt for √. Any form with the same value counts (7/2 = 3.5).
- One question at a time: Back, Next, Mark for review and the question list at the bottom. A calculator is on the screen.
- At the end: your percent and grade, every question right or wrong, why a wrong choice is wrong, and its step-by-step solution. Then practise the lesson with new questions.
Your answers and results are kept in this browser only, so you can close the page and come back.
1 Question 1
Prove the sum of two even numbers is evenType the answer.
2 Question 2
Prove the product of two even numbers is evenType the answer.
3 Question 3
Prove if n is even, then n2 is evenType the answer.
4 Question 4
Prove the product of two odd numbers is oddType the answer.
5 Question 5
Prove the product of an even number and an odd number is evenType the answer.
6 Question 6
Prove if n is odd, then 5n + 1 is evenType the answer.
7 Question 7
Prove the sum of two multiples of 7 is a multiple of 7Type the answer.
8 Question 8
Prove if n is odd, then n2 + n + 1 is oddType the answer.
9 Question 9
Prove the sum of two consecutive odd numbers is a multiple of 4Type the answer.
10 Question 10
Prove the product of two multiples of 4 is a multiple of 16Type the answer.