One basic sentence pattern in English consists of a subject, a linking verb, and a subject complement: Jack is a lawyer. Because the subject complement (lawyer) names or describes the subject (Jack), it is sometimes mistaken for the subject. (See B2-b on subject complements.)

Tent and bag are the subject, not equipment.

Force is the subject, not children. If the corrected version seems too awkward, make children the subject: Children are a major force in today’s economy—as consumers, decision makers, and trend spotters.