This is the answer key of Volume 4 of the entire set of 12 volumes of word problems solving strategies. If you want to set a solid foundation in math, grasping the techniques on solving word problems is the key to it. This set of books teaches you the techniques and strategies you need to solve word problems.
Sample question in this volume:
Grandma raises 18 more chickens than ducks. If the number of chickens is 3 times as many as the ducks, how many ducks and chickens does Grandma raise respectively? (Video)
Reasoning and solution:
3 times means 3 groups. From "the number of chickens is 3 times as many as the ducks," we know that the number of ducks is the amount in 1 group and the number of chickens is the total amount in 3 groups.
The amount difference, 18, is in the difference between groups, (3-1), 2 groups. Therefore, the amount in 2 groups is 18, so we divide the difference between numbers of groups, 2, into the difference between the amounts in the groups, 18, to find the amount in one group:
18