arreglárselas

A fixed reflexive idiom meaning to manage, cope, or get by — often with a specific challenge attached: arreglárselas para + infinitive ("to manage to do something") or arreglárselas sin algo ("to make do without something"). The pronoun cluster (se + las) is invariable; it doesn't refer to any actual feminine plural noun.

• No sé cómo se las arregla con tan poco dinero. — I don't know how she manages with so little money.
• Nos las arreglaremos sin coche esta semana. — We'll manage without a car this week.
• Siempre te las arreglas para llegar tarde. — You always manage to arrive late.

Dropping or changing the las — learners sometimes try arreglárselo or just arreglarse, but the expression is fixed as arreglárselas; the las is a frozen part of the idiom, not a real object pronoun to be matched to context.