L5 · Arrays for products and quotients; division as repeated subtraction
“I can use an array to show a product and its quotients. I can divide by subtracting the same number over and over - and count the subtractions.”
An array has 4 rows with 6 tiles in each row. Step 1 (product): rows x in-each = 4 x 6 = 24 tiles. Step 2 (turn it): the same array is 6 columns of 4 - 6 x 4 = 24 (L3's commutative property, visible). Step 3 (quotients live here too): 24 tiles in rows of 6 -> how many rows? 24 / 6 = 4. And 24 / 4 = 6. One array holds a whole family: two products and two quotients, all built from 4, 6 and 24.
One array can show both 24 / 6 and 24 / 4 because...
An array of 5 rows of 7: 5 x 7 = 35 (and 35 / 5 = 7, 35 / 7 = 5)
"An array of 3 rows of 9: 3 x 9 = ___ and 27 / 3 = ___" -> 27; 9
10 scored questions with a 3-rung hint ladder. Mastery needs 8/10 plus both gate questions.