Multiplication as repeated addition and Division as repeated subtraction

Multiplication as repeated addition and Division as repeated subtraction

1. Example: 5 x 4= ____ 5 groups of 4 4 + 4 + 4 + 4 + 4= 20 Example 2: 4 x 5= ____ 4 groups of 5 5 + 5 + 5 + 5= 20 Multiplication as Repeated Addition

2. 4 5 x 4= 20 X 5 20 4+ 4+4 +4 +4= 20 5 4 x 5 = 20 X 4 20 5+5+5+5=20

3. Write the multiplication sentence using the given addition facts: 1. 3 + 3 + 3 + 3+ 3= 15 2. 15 + 15 + 15 =45 3. 21 + 21 = 42 4. 6 + 6 + 6 + 6 + 6 + 6 +6 = 42 5. 10 + 10 + 10 + 10 + 10= 50 Exercise:

4. Show the repeated addition for the following multiplication sentence: 3 x 5= 6 x 2= 9x 3= 2 x 10= 4 x 8=

5. Example: 20 ÷ 4 = ____ 20- 4 - 4 - 4- 4- 4=0 How many times did we subtract 4 until we have 0? 5 So 20 ÷ 4 = 5 Example: 20 ÷ 5= ____ 20 - 5 - 5 - 5 - 5 = 0 How many times we subtracted 5 until 0? 4 So 20 ÷ 5 = 4 Division as Repeated Subtraction

6. Example : 20 ÷ 5 = 4 20 - 5 - 5 - 5 - 5 = Correct: 20- 5 = 15 wrong: 20- 4 =16 15- 5 = 10 16- 4= 12 10- 5 = 5 12- 4 = 8 5- 5 = 0 8- 4 = 4 4-4 = 0 In repeated subtraction (illustrating division), the subtrahend is the divisor, not the quotient.

7. Write the division sentence using the given subtraction facts: 30- 3 - 3 – 3 – 3 – 3 – 3 – 3 – 3 – 3 – 3 = 0 26- 13- 13 = 0 48 – 12 – 12 – 12- 12= 0 15 – 5 – 5- 5 = 0 21 – 7 – 7 – 7 = 0