Understanding the Product of Eleven and Two-Digit Numbers

This video tutorial explains a pattern for multiplying the number 11 by two-digit numbers. It covers two cases: when the sum of the digits is less than 10 and when it is 10 or more. For the first case, the product is formed by placing the sum of the digits between the original digits. For the second case, an exchange is performed to adjust the middle digit. Several examples are provided to illustrate each case.

What is the first step in determining the product of 11 and a two-digit number when the sum of the digits is less than 10?

• Multiply the digits together

• Add the digits together

• Divide the digits

• Subtract the digits

In the example of 11 times 43, what is the digit placed in the middle?

• 7

• 3

• 4

• 1

For the product of 11 times 32, what is the resulting number?

• 332

• 320

• 323

• 352

When multiplying 11 by 18, what is the middle digit in the product?

• 1

• 8

• 0

• 9

What is the key difference in the process when the sum of the digits is greater than or equal to 10?

• Add an extra digit

• Subtract a digit

• Perform an exchange

• No difference

In the example of 11 times 87, what is the final product after performing the exchange?

• 985

• 870

• 957

• 875

For 11 times 55, what is the digit placed in the hundreds place after the exchange?

• 5

• 6

• 1

• 0

What is the final product of 11 times 76 after performing the necessary exchange?

• 760

• 763

• 876

• 836

In the final example, what is the sum of the digits of 76?

• 14

• 13

• 15

• 12

What is the purpose of performing an exchange in the second case?

• To add more digits

• To subtract from the total

• To adjust the place values correctly

• To simplify the calculation