Multi-digit Multiplication | Parent Activity

Dear Families,

Your fourth grader is learning to multiply larger numbers - up to 4-digit by 1-digit and 2-digit by 2-digit! They're using strategies like the area model, partial products, and the standard algorithm. These activities help connect classroom learning to real life.

Why This Matters for the FAST Test

The Florida FAST assessment tests multi-digit multiplication through computation problems AND word problems. Students who understand WHY multiplication methods work (not just the steps) can catch their own errors and solve unfamiliar problems with confidence.

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Activity 1: Grocery Store Multiplication

Real-world multiplication with prices

While shopping, pick an item and a quantity: "We need 24 juice boxes. Each pack of 6 costs $4."
Ask: "How many packs do we need?" (24 / 6 = 4 packs)
Then: "What's the total cost?" (4 x $4 = $16)
Try larger numbers: "The store sold 45 cases of water today. Each case has 32 bottles. How many bottles total?"
Encourage estimation first: "About how many? 45 is close to 50, 32 is close to 30... so about 1,500!"

Tip:

Use receipts after shopping! Pick items and create word problems: "If we bought 3 times as many bananas, how much would that cost?"

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Activity 2: Build an Area Model

Visual understanding with rectangles

Use graph paper, tiles, or draw on paper to make rectangles.
For 23 x 14, draw a rectangle that's 23 units by 14 units.
Divide it: 23 = 20 + 3, and 14 = 10 + 4. Now you have 4 smaller rectangles!
Calculate each section: 20x10=200, 20x4=80, 3x10=30, 3x4=12
Add them up: 200 + 80 + 30 + 12 = 322
Check with a calculator - it matches!

Why Area Models?

This method shows that multiplication finds the area of a rectangle. It also reveals the partial products that are "hidden" in the standard algorithm!

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Activity 3: Mental Math Challenge

Build number sense and flexibility

Practice "friendly number" multiplication: "What's 25 x 8?"
Strategy: 25 x 8 = 25 x 4 x 2 = 100 x 2 = 200 (since 25 x 4 = 100)
Try: "What's 15 x 12?" (Think: 15 x 10 + 15 x 2 = 150 + 30 = 180)
Practice doubling: 24 x 5 = 24 x 10 / 2 = 240 / 2 = 120
Make it a game: Time how fast you can solve 5 problems mentally!

Tip:

Mental math builds number sense! Even if your child uses the algorithm on paper, these strategies help them estimate and check their work.

Questions to Ask Your Child

"Show me how you would solve 34 x 26 using the area model."
"Why do we write a zero (or shift over) when we multiply by the tens digit?"
"If 45 x 32 = 1,440, what would 45 x 33 be? How do you know?"
"About how much is 78 x 42? How did you estimate?"
"What's an easy way to multiply by 25? By 50?"
"Can you explain what partial products means?"

Resumen en Espanol

Multiplicacion de numeros grandes: Su hijo esta aprendiendo a multiplicar numeros de hasta 4 digitos por 1 digito (como 2,345 x 7) y 2 digitos por 2 digitos (como 34 x 56). Usan el modelo de area, productos parciales, y el algoritmo tradicional.

Actividades en casa:

Supermercado: Multiplique precios por cantidades mientras compra.
Modelo de Area: Use papel cuadriculado para dibujar rectangulos y ver los productos parciales.
Matematicas Mentales: Practique estrategias como duplicar, usar numeros amigables.

Pregunta clave: "Por que escribimos un cero cuando multiplicamos por las decenas?"

Home Activity: Multi-digit Multiplication