Instead of giving children word problems that only use the operation they just studied, mix them up. Write word problems so the children have to read it to find out how to solve it. Math books typically train students to just look for the two numbers in the word problem and perform the operation they're studying; real life doesn't work that way. If you're studying subtraction, include addition problems and some problems that require both addition and subtraction. For example, John and Karen want to buy a carton of ice cream. John has $2.89 and Karen has $3.45. The ice cream costs $5.30. How much money will they have after buying the ice cream?
Take every opportunity possible to relate word problems to things that interest the children. For example, if the problem involves two children who want to pool their money together to purchase an item, ask the children to supply the children's names, the amount of money the children have, what the children want to buy or how much it costs.
Provide some word problems that only requires the students to determine the operations needed to solve the problem. This gives the children extra practice in reasoning, often the more difficult part of the problem, without taking the time required to do the computation.
Children learn best using their visual and tactile senses. Incorporate visuals and manipulatives with the word problems. For example, two children (Casey and Gina) collect eggs from the chicken coop in their yard. If they collected 24 eggs altogether and Gina collected twice as many eggs as Casey, how many eggs did each child collect? There are multiple ways to visualize this problem. Have a girl pretend to be Gina and a boy pretend to be Casey. Give Gina two baskets and Casey one basket. Using 24 plastic eggs, put one egg in each basket until all 24 eggs have been used. Another way to represent this word problem would be for each student to have three empty egg cartons. Label two of them "Gina" and one of the cartons "Casey." Give each student 24 plastic eggs and let them work out the problem themselves.