Multi-digit Multiplication | Student Worksheet

The Big Idea

When multiplying large numbers, we use place value to break them into smaller parts!

23 x 45 = (20 + 3) x (40 + 5) - multiply each part, then add!

Draw a rectangle and break each number into tens and ones.

Example: 23 x 45

Add all parts: 800 + 100 + 120 + 15 = 1,035

Write out each multiplication, then add all the products.

    23
  x 45
  ----
    15  (3 x 5)
   100  (20 x 5)
   120  (3 x 40)
   800  (20 x 40)
  ----
 1,035

Tip: The partial products are the same as the area model boxes!

The traditional method - multiply in steps and regroup.

      23
    x 45
    ----
     115  (23 x 5)
    920   (23 x 40 - notice the zero!)
   ----
   1,035

Use place value - multiply each digit by the one-digit number.

Example: 2,456 x 7

    2,456
      x 7
    -----
       42  (6 x 7)
      350  (50 x 7)
    2,800  (400 x 7)
   14,000  (2,000 x 7)
    -----
   17,192

Or use the standard algorithm with regrouping!

1. Use the area model to solve 34 x 26

Answer:

2. Solve 47 x 52 using any method. Show your work.

Answer:

3. Solve 3,825 x 6 using any method. Show your work.

Answer:

4. Solve 1,234 x 8 using any method. Show your work.

Answer:

5. A school has 28 classrooms. Each classroom has 32 desks. How many desks are there in total?

Answer: desks