ruiruima

3 Questions
0 Answers

+1

9

1

+17

Number theory

How many positive integers are not less than the sum of their divisors?

ruiruima 14 Jan 2024

+2

5

1

+17

Ordered pairs of primes

How many ordered pairs of primes (a,b) satisfy a+b=22?

ruiruima 13 Jan 2024

+2

6

1

+17

Arithmetic sequence

The 80th term of an arithmetic sequence is twice the 30th term. If the first term of the sequence is 7, what is the 40th term?

ElectricPavlov ●

ruiruima 12 Jan 2024