Turnarounds and regrouping factors

1. 5

5 rows of 6 is the same array as 6 columns of 5: turning it round doesn't change how many dots.

So 5 × 6 = 6 × 5. The missing number is 5.

2. 6

6 rows of 7 is the same array as 7 columns of 6: turning it round doesn't change how many dots.

So 6 × 7 = 7 × 6. The missing number is 6.

3. 6

6 rows of 5 is the same array as 5 columns of 6: turning it round doesn't change how many dots.

So 6 × 5 = 5 × 6. The missing number is 6.

4. 4

4 rows of 8 is the same array as 8 columns of 4: turning it round doesn't change how many dots.

So 4 × 8 = 8 × 4. The missing number is 4.

5. 2

2 rows of 5 is the same array as 5 columns of 2: turning it round doesn't change how many dots.

So 2 × 5 = 5 × 2. The missing number is 2.