The Recreational District has added a new Little

League field. Each of the 4 bases is 75 feet apart

and the bases make a perfect square on the

field. Aubrey hit a homerun and ran the bases.

How far did he run?

Are you trying to find the area or the perimeter?

How do you know?

Application Problem

Read

Square, 75 feet each side

Illustrate

Compute75 x 4 =

(70 x 4) + (5 x 4) = 280 + 20 =

300 ft. =

Explain

Rectangular Sections compared to

Standard Algorithm

  10 6  

10 100 60 160

2 20 12 +32

  120+

72192

16

X12

32

160

192

  20 4  20 400 80 480

5 100 20+12

0

  500100

600

1. 25 x 24

  30 8  

90 2,700 560 3,260

3 90 24 +114

  2,790 584 3,374  60 5  

40 2,400 200 2,600

2 120 10 +130

  2,520 210 2,730

2. 93 x 38

3. 42 x 65

Practice Problems

Mental Math and Multiplication

Step 1: Break apart 298 300 – 2 = 298

Step 2: Write a number sentence. (6 x 300) – (6 x 2)

Step 3: Solve1800 – 12 = 1788

1. 6 x 298

Mental Math and Multiplication

Step 1 – Estimate with one of the numbers. 214 ≈ 200 and 8 ≈ 10

(≈ means about)

Step 2 – Write a number sentence. (8 x 200) + (8 x 14) =

or (10 x 214) – (2 x 214) =

Step 3 – Solve 1600 + 112 = 2140 – 428 = 1712

2. 8 x 214

Mental Math and Multiplication

Step 1 – Remember how to multiply by multiples of 10.

Step 2 – Write a number sentence. (10 x 50) + (4 x 50) =

Step 3 – Solve 500 + 200 = 700

3. 14 x 50

Mental Math and Multiplication

Step 1 – Use the Commutative Property to change the order of the factors

2 x 50 x 9Step 2 – Write a new number sentence.

(2 x 50) x 9 =

Step 3 – Solve 100 x 9 = 900

4. 2 x 9 x 50

Independent PracticeArea and Perimeter – WK p. 175 problems 3 and 4

Find both the area and perimeter.Rectangular MultiplicationSolve 1. 45 x 91 2. 87 x 56

Multiplication and Mental Math – WK 55 problems 1–4

Tell the strategy you used.

Independent PracticeAn orchard has 6 rows of apple trees with 8 tree in each row. Each apple tree is ten feet wide/across. What is the perimeter of the orchard?Mrs. DiCarlo decided to add some pear trees to the orchard. She planted 5 rows of pear trees with 9 trees in each. How many pear trees does she have?The pear trees are each ten feet wide/across. Which part of the orchard covers more area, the apple or the pear?