PR1ME I Whole Class (cont.) WEEK 2 I DAY 3
Lesson 2: Problem Solving
Learn
Word problems
Learning Outcome: •
Solve a word problem by forming an algebraic equation involving one operation
Overview This word problem requires students to form an algebraic equation involving one operation. Go through the word problem using the 4-step Understand-Plan-Answer-Check process. Have students read the word problem and identify the key information. This will help them understand the word problem and interpret it correctly.
1. Understand the problem. −
4. Check whether your answer is correct. −
Explain to students that they must find the unknown z , which is the number of guppies.
Guide students to check their answers by seeing if they get a total of 38 fishes when they substitute 17 for z in the expression z + 21. Since 17 + 21 = 38, conclude that the answer is correct.
2. Plan what to do. −
Point out to students that they can form an algebraic equation in terms of z to solve the problem.
3. Work out the Answer . −
Guide students to form an algebraic equation in terms of z . Have them see that z guppies and 21 angelfish add up to 38 fishes. − Have a student write the algebraic equation on the board. He/she should form the equation z + 21 = 38. − Point out to students that they can represent the algebraic equation with a bar model. − Draw a part-whole bar model as shown in the though bubble. − Explain to students that the whole bar represents the total number of fishes that Evan has. Since he has two types of fishes, we split the bar into two parts. Have them also see that z and 21 are both parts of the whole, 38. − Lead students to see that to find the unknown part, z , they need to subtract the known part, 21, from the whole, 38. − Explain to students that even though they can use the guess and check method to solve the equation, it is easier to use the balance method in this case. − Remind them to carry out the same operations on both sides of the equation until only the unknown number remains on one side of the equation. − Get another student to solve the equation on the board using the balance method and see that z = 17. Get him/her to conclude that 17 of Evan’s fishes are guppies.
56 Scholar Zone Summer: Math
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