‹ Grade 4 Mathematics class

Lesson 2 of 10 · Chapter 2

The Festival Planner

You lead the planning committee for the Fall Festival. In this lesson you multiply big numbers with the area model, share money fairly with long division, and lay out the festival grounds with area and perimeter, the way a real event planner does.

Choose how you want to learn

You can change this any time. Press Listen on any part to hear it read aloud. Grown-ups: read along with younger children.

For parents. This class is part of GSU’s free Homeschool program. Stuck on a problem, or want it explained another way? Ask GENO, GSU’s free tutor, with the GENO button on this page. He can walk you and your child through any step, in your language.

Part 1

Multiplying big numbers

To multiply two big numbers, break them into parts.

15 × 25: think of 15 as 10 + 5 and 25 as 20 + 5. Multiply each part, then add.

That is the area model. Always estimate first.

The area model draws a grid. Rows are the parts of one number, columns are the parts of the other. For 15 × 25: 10 × 20 = 200, 10 × 5 = 50, 5 × 20 = 100, 5 × 5 = 25. Add the four boxes: 375.

The standard algorithm does the same work in two rows. For 34 × 27: 34 × 7 = 238, then 34 × 20 = 680. Add the partial products: 918.

Then check it makes sense. 18 boxes of 24 balls is 432 balls; 432 is more than 375 students, so there are 57 extra prizes.

“For larger numbers, we can use the area model (breaking numbers into parts) or the standard algorithm.”

“Always estimate first!”

Multiply for the festival. Type the answer and press Check. Three right to finish.

Part 2

Long division: sharing fairly

Division shares a total into equal groups.

Long division follows four steps: Divide, Multiply, Subtract, Bring down. Repeat until done.

Sometimes a little is left over. That is the remainder.

$1,452 ÷ 4 charities: 14 ÷ 4 = 3, remainder 2. Bring down 5 to make 25: 25 ÷ 4 = 6, remainder 1. Bring down 2 to make 12: 12 ÷ 4 = 3. Each charity gets $363. Check: 363 × 4 = 1,452.

$1,457 ÷ 4 is 364 remainder 1. Math says $1 is left over; people decide what to do with it, like giving one charity $365 or buying a thank-you card.

“Long division follows a pattern: Divide, Multiply, Subtract, Bring down.”

“Real-world decisions go beyond just the math!”

Share it out. If something is left over, type it like 364 R1. Three right to finish.

Part 3

Area and perimeter

Area is the space inside a shape. For a rectangle: length × width. It is measured in square feet.

Perimeter is the distance around. Add all four sides.

The festival plot is 60 ft by 40 ft. Area: 60 × 40 = 2,400 square feet, the ground you cover. Perimeter: 60 + 40 + 60 + 40 = 200 feet, the fence you buy.

A short way for perimeter: P = 2 × length + 2 × width. Area answers “how much covers it?” Perimeter answers “how much goes around it?”

“Area: The space inside a shape. For rectangles: Area = Length × Width”

“Perimeter: The distance around a shape. For rectangles: P = 2 × Length + 2 × Width”

Look at the plot. Find the area or the perimeter it asks for. Three right to finish.

Part 4

Missing sides and cut-out shapes

Sometimes you know the perimeter or area and need a missing side. Work backward.

For an L-shape, take the big rectangle and subtract the cut-out.

Perimeter 48 ft, length 14 ft: 48 = 2(14) + 2W, so 48 = 28 + 2W, 20 = 2W, and the width is 10 ft.

Area 72 sq ft, length 9 ft: the width is 72 ÷ 9 = 8 ft.

An L-shape: a 20 × 10 rectangle is 200 sq ft; cut out 8 × 6 = 48 sq ft; 152 sq ft remain. A border around a pool is the outer rectangle minus the pool.

“48 = 28 + 2W”

“Remaining area: 200 - 48 = 152 sq ft”

Find the missing side or the remaining area. Three right to finish.

Part 5

Planning the order: how many boxes?

Planners multiply to find how many are needed, then divide to find how many boxes to order.

If the division leaves a remainder, you need one more box.

15 classes × 25 students × 3 prizes = 1,125 prizes. Boxes hold 48. 1,125 ÷ 48 = 23 remainder 21. Twenty-three boxes leave 21 children with nothing, so order 24 boxes.

This is where the remainder matters most: in real planning you round up to cover everyone.

“Will 18 boxes of balls be enough for one prize per student?”

How many boxes must you order so nobody goes without? Three right to finish.

Part 6

Read the whole chapter

Here is all of Chapter 2, “The Festival Planner”, exactly as the book tells it, with every worked example, all 60 practice problems and the Action Report. Press Listen to hear it read aloud, or open it and work along with a pencil.

Open Chapter 2

Part 7

Try it at home

Do these with your family. Tick each one when it is done.

Part 8

Your “Festival Planner” card

Fill it in, then print it for the fridge. Nothing you type here leaves this device.

Festival Planner’s Card

Global Sovereign University · Grade 4 Mathematics, lesson 2

A multiplication I used
Its area model
How I shared fairly
My room's perimeter
My room's area

Long division

  1. Divide
  2. Multiply
  3. Subtract
  4. Bring down. Repeat until done.

Part 9

Check yourself

6 questions. Pick an answer. If it is not right, read the hint and try again.

Lesson 2 complete.

You can multiply big numbers with the area model, divide with remainders, find area and perimeter, work out a missing side, and order enough supplies. Next: Lesson 3, The Pet Shop Owner. Back to the class.

Homeschooling Math Books for Kids: Grade 4, cover

Homeschooling Math Books for Kids: Grade 4 by Dr. Gene A Constant. This lesson is Chapter 2, and the whole chapter is on this page.

GSU is a 501(c)(3) nonprofit and book sales are its only income. A purchase is not a tax-deductible donation. This lesson is free and always will be.

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