Problem
COM-B1-M01-P005 Sum of Two Positive Numbers
#5
★☆☆☆☆ Level 1 of 5
How many pairs of positive integers \((a,b)\) satisfy \(a+b=7\)?
Choose \(a\); then \(b\) is determined.
The number \(a\) can be \(1,2,3,4,5,6\). After choosing \(a\), \(b=7-a\) is positive and determined. Answer: \(6\).
Simple counting by a parameter.