Tip on Cross Multiplication of Two Digit Numbers

Cross Multiplying Two Digit Numbers

Problem : 16 x 28

Step1:

First, write your problem down, sitting on top of each other, like you would do when multiplying normally.

   1 6

x 2 8-------

Step2:

Multiply the numbers in the ones place and put the product underneath the problem as shown. In this case, 8*6 is greater than 10 (48).

   1 6

x 2 8-------

    48

Step3:

Cross-multiply the ones with the opposing tens and add them together. In this case, (2*6) + (1*8) = 20. Write 20 underneath 48 one space to the left (ending on the tens column)

   1 6

x 2 8-------

    48

  20

Step4:

Multiply the tens. 1*2 = 2. Place this product another space to the left, in the hundreds column as shown.

   1 6

x 2 8-------

    48

  20

  2

Step5:

Now, add the products. Add the three rows as you do in normal multiplication method. The sum of the three rows you created equal 448, our answer.

   1 6

x 2 8-------

    48

  20

  2

-------

  448