Multiplication as repeated addition and Division as repeated subtraction
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This document provides examples and exercises demonstrating multiplication and division as repeated addition and subtraction. For multiplication, it shows writing multiplication sentences as the repeated addition of the multiplicand. For division, it illustrates writing division sentences as repeatedly subtracting the divisor from the dividend until reaching zero. Exercises have students write multiplication and division sentences using given addition and subtraction facts.
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: 1. 3 x 5= 2. 6 x 2= 3. 9x 3= 4. 2 x 10= 5. 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 = 0 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: 1. 30- 3 - 3 – 3 – 3 – 3 – 3 – 3 – 3 – 3 – 3 = 0 2. 26- 13- 13 = 0 3. 48 – 12 – 12 – 12- 12= 0 4. 15 – 5 – 5- 5 = 0 5. 21 – 7 – 7 – 7 = 0