Course Guide - USAID Teacher Education Project

. Have students devise ratio problems that relate to real life situationsc. Introduce solving proportions for an unknown by using equivalent fractionsd. Relate each of the above to children’s thinking9. Class Activitiesa. Begin by describing the scenario of a family with 3 boys and 1 girl. Havestudents quickly write all the ways they can think of to express that relationshipusing both words (e.g., “I have three times as many sons as daughters.” or“Three-fourths of my children are boys.”) and in symbolic representation (3:1,1/4, etc.).b. Ask for and chart their responses. Be aware that some students will use thecomparison model of subtraction to discuss the relationship (I have two moresons than I have daughters).c. Use student responses to launch a comprehensive class discussion of 1) howpart-to-part and part-to-whole relationships are different, 2) that part-to-wholerelationships can be expresses as fractions or percents, and 3) that the order ofnumbers in a ratio is important.d. As part of this discussion, have students generate several scenarios where ratiosmay be found in real life situations.e. Ask students how they could solve 8/36 = 20/x. If they mention crossmultiplying,ask them to explain how it works. Then ask how they might usewhat they learned about equivalent fractions to solve for x. Have them work inpartners and use this method to discover a solution.10. Assignment:Have students read Fractions, Units, and Unitizing (http://tinyurl.com/Fractions-Units) with its explanation of part-to-part, part-to-whole thinking.What do they think about the last section and how it relates to adding fractions?Can they think of a real life scenario where adding part-to-part might occur?