Name: Jennifer
Level of question: Middle (6-9)
Person asking: teacher

  1. A cake recipe calls for 3 1/4 cups of flour. You already put in 1 3/4 cups. How much more should you add?

  2. You have 3/4 yard of ribbon. How many 1/8-yard pieces can you cut the ribbon into?
Hi Jennifer,

Think in terms of what you would do to actually complete each task described. This is a "constructive solution". You don't actually need the cups, flour and ribbon; you can mentally "construct a solution".

  1. Imagine that you add one more cup of flour so that you have added in total 2 and 3/4 cups. If you now add a further 1/4 of a cup your total is increased to 3 cups. Thus you now need one more 1/4 cup to reach the required 3 and 1/4 cups. Thus in total you need to add 1 cup and two 1/4 cups or, in other words, 1 and 1/2 cups of flour.

  2. Imagine that you have the ribbon in front of you.

    Mark it off into three, 1/4 yard pieces. Each 1/4 yard piece can be cut in half to yield two, 1/8 yard lengths giving you altogether six, 1/8 yard pieces of ribbon.
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