If Jack gives Carl five marbles, he will have only 10 marbles left. Encourage students to make up several different problem situations that require the given sentence. Two months later I visited that same school. Our students are really getting good at writing correct sentences for solving word problems. Much of the enjoyment happens within mathematics itself.
Many teachers use teaching techniques that motivate their students to want to learn mathematics.
Sponsor in-service workshops for teachers that emphasize and indicate fun activities within mathematics. Make sure that the leaders of those workshops know and understand mathematics well enough to not get caught up in pedagogical ideas that may or may not apply to the teaching of mathematics. There is an endless supply of fun, useful mathematical activities, such as creating magic squares, using games to review and master basic math concepts and skills, number tricks like those in this column, using different number bases, etc., etc., etc. Before that he was the state mathematics supervisor for the Department of Public Instruction. His graduate degrees are in pure mathematics and educational administration.