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Represent repeated addition and arrays as multiplication, and

By Maria Davis,2014-03-31 21:26
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Represent repeated addition and arrays as multiplication, and

Represent repeated addition and arrays as multiplication, and sharing and repeated subtraction (grouping) as division; use practical and informal written methods and related vocabulary to support

multiplication and division, including calculations with remainders

(Objective repeated in Block E Units 1, 2 & 3)

Ask the question Q Every day at break Sam has 5 grapes for his snack. How many grapes does he eat at school during the week? Q What calculation do we need to do? Establish that Sam eats grapes on Monday, Tuesday, Wednesday, Thursday and Friday. Q How many days does he eat grapes? Explain it is 5 days. Q How many grapes does he eat each day? Explain it is 5. Q So how can we work out 5 lots of 5? Discuss 5 + 5 + 5 + 5 + 5 = 25 Q Do you know another way to write this? Explain it can be written as 5 lots of 5. Q Do we know a sign that represents lots of? Discuss the x sign and what it means. Write up vocabulary related to x eg lots of, groups of, multiply, times. Q How do we work out 5 x 5? Represent 5 x 5 as an array, using grapes 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Explain by adding 5 + 5 + 5 + 5 + 5 or we could use the 5 times table and count up in 5’s. Q So how many grapes does Sam eat during a week at school? Establish answer is 25 grapes. Discuss methods used. Activities. Children make up own problems involving the vocabulary of x and show answer using array of repeated addition.

Start with question. Q How many wheels are there on 3 cars? Q What calculation do we need to do? Discuss with partner and take responses, 4 x 3 or 3 x 4 Q Are these the same? Do they give the same answer? Discuss they are the same and prove drawing 2 arrays x x x x x x x x x x x x x x x x x x x x x x x x Q How do we work out 4 x 3?

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Children talk to partner and explain methods, ie 4 + 4 + 4, using an array, counting up in 4’s 3 times or 3 + 3 + 3 + 3, counting up in 3’s 4 times. Write 6 x 2 = ; Q What could be the possible question to go with this calculation? Discuss in pairs, take responses. Model how to work it out using repeated + and arrays. Activity Children given multiplications with ; to represent answer, which they invent own questions for. Show working in arrays and repeated +.

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