Multiplying up to Three Digits Using the Standard Algorithm—Let's Practice!

Multiplying up to Three Digits Using the Standard Algorithm—Let's Practice! exercise

• What are the two simple steps to find the answer when multiplying two numbers?

  Hints

  5 x 7

  Is this on the left or right?

  Continue with 5 x 2.

  Finally, combine the results together to find the final answer.

  Solution

  Multiply each digit of the bottom number by each digit of the top number, starting from the right.

  Add up all the results to find the final answer.

• Solve the multiplication problem.

  Hints

  Begin by focusing on the individual digits of each number, starting from the right.

  Start with 5 x 8.

  Remember, if the answer is bigger than 9, we put the extra ones in the tens place.

  So, when we do 5 x 8, we get 40.

  We write down 0 in the ones place and put 4 in the tens place.

  After completing the multiplication for each pair of digits, sum up the results to obtain the final answer.

  Solution

  38 x 5 = ?

  5 x 8 = 40

  Put 0 in the ones place, and regroup the 4 with the tens.

  5 x 3 = 15

  15 + 4 = 19

  38 x 5 = 190

• What is 46 x 8 ?

  Hints

  Begin by multiplying the ones place of the bottom factor (8) by the ones place of the top factor (6).

  If the product of the ones place is greater than 9, regroup the extra tens to the next place value.

  After regrouping, multiply the ones place of the bottom factor (8) by the tens place of the top factor (4).

  Remember to add the regrouped tens to this product to get the final result for the tens place.

  Solution

  46 x 8 = 368

  1.8 x 6 = 48

  2.Put eight in the ones place, and regroup the four with the tens.

  3.8 x 4 = 32

  4.32 + 4 = 36

• What is 438 x 3?

  Hints

  Start by multiplying the bottom factor (3) by the ones place of the top factor (8).

  Remember to carry over if needed.

  Then continue with the tens place (3 times 3).

  Finally, do the multiplication for the number in the hundreds place, (3 x 4).

  Solution

  3 times 8 is 24, so write 4 in the ones place and carry over 2.

  3 times 3 is 9.

  9 + 2 = 11. We write 1 in the tens place and carry over 1.

  3 times 4 is 12, but we need to account for the carried-over 1 from the previous step.

  3 times 4 plus 1 is 13.

  So, the product of 438 × 3 is 1,314.

• Can you solve the multiplication?

  Hints

  Multiply the bottom factor (9) by the ones place of the top factor (3) to get the result for the ones place.

  Multiply the bottom factor (9) by the tens place of the top factor (1) to get the result for the tens place, and then combine the results for the final answer.

  Solution

  13 x 9 = 117

  1.9 x 3 = 27

  2.9 x 1 = 9

  3.9 + 2 = 11

• Solve the different multiplication problems.

  Hints

  Focus on one number sentence at a time.

  Use the standard multiplication algorithm for each sentence, starting with the ones place.

  Pay attention to regrouping if the product is greater than 9 in any step.

  Solution

  324 x 6 = 1,944

  58 x 7 = 406

  338 x 4 = 1,352

  96 x 6 = 576