Lesson 21 Objective: Solve two step word problems involving all four operations and assess the reasonableness of answers.

Let’s count by fours to 40 4 40 16 24 8 36 12 20 28 32

Count by sixes to 48 Count in threes to 30 6…12…18…24…30…36…42…48 Count in threes to 30

5 X 5 = ____ 25

5 X 3 = ____ 15

5 X 9 = ____ 45

40 5 X 8 = ____

8 4 X 2 = ___ 8 2 X 4 = ___

Multiply by 5 Pattern Sheet 2 minutes This ‘sand timer’ will start on a mouse click anywhere on the slide. The ‘sand’ will drain from the top section to the lower section and when completed will show the word ‘End’. To change the timings of this timer, you need to enter the animation settings, and change the timings for the Isosceles Triangles. There will be 2 that need changing (to the same amount) – one animates the top triangle emptying, whilst the other animates the bottom triangle filling. When you change the timings these have to entered as a number of seconds. End

3 brothers share the binders. How many folders does each There are 4 boxes with 6 binders in each one. 3 brothers share the binders. How many folders does each Brother get?

Each brother gets 8 binders. 1 2 3 4 ? Binders 6 X 4 = 24 binders Divide the binders among 3 brothers: 24 ÷ 3 = 8 binders Each brother gets 8 binders.

Concept Development: You will be divided into groups of about 4 students. Each group will receive a word problem from today’s problem set to solve. Use the Read – Draw – Write Method to solve. Read and analyze the problem together. Determine known and unknown information. Discuss how to model the problem. On your chart paper, DRAW AND LABEL A MODEL. Discuss and agree on the steps needed to solve the problem. WRITE AND SOLVE EQUATIONS; Assess the reasonableness of your solution. (Ask, “Does our answer make sense? How do we know?) Write A COMPLETE SENTENCE to answer the question. Prepare a mini presentation to explain your work. Be prepared to answer questions.