Objective: Students will understand multiplication as adding equal rows and columns in arrays.
0:00 On to lesson 3, practice with arrays. To multiply a raise, count how many rows there are. Rows are horizontal and go from left to right.
0:11 How many rows are in this array? There are four rows in the array. 1, 2, 3, 4. Next count the columns.
0:24 Columns and vertical going from top to bottom. Thanks for watching. How many columns are in this array? There are three columns in this array.
0:35 1, 2, 3. The repeated addition expression for the array is 3 plus 3 plus 3 plus 3. I added four groups of three.
0:47 One multiplication equation represents the equal rows of squares. Layers. Four groups of three equals twelve. Three times four equals twelve squares and all.
1:03 Now you try. One multiplication equation represents the equal rows of squares. You How many squares are there? There are three rows of six squares.
1:17 Three times six equals eighteen smaller squares and all. You What’s the mistake? Three times five equals eight. This is three rows of five, not a row of three and a row of five.
1:41 So three times five equals fifteen. The factors are right but the product is wrong. There are three groups of five squares.
1:51 Three times five is fifteen, not eight. The numbers were added instead of multiplied. You