Page 31 - 新思维数学活动用书7 样章
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2 Expressions, formulae and equations
15 In a magic square, the rows, columns and diagonals all add up to the same number. Copy the
magic squares in parts a and b.
a Write the numbers 1 to 9 in this magic square, so that all the rows, columns and diagonals
add up to 15.
You can use each number only once.
Three numbers have been written in the magic square for you.
8
5
9
b Write the algebraic expressions from the cloud in the magic square, so that all the rows,
columns and diagonals add up to 3b.
a + b
b – c
b – a – c
a + b – c b
b + c
b – a b + c – a
a + b + c
2.4 Expanding brackets Key words
brackets
You can use a box method to multiply numbers together, like this: expand
4 × 16 = 4 × (10 + 6)
× 10 6 Tips
4 40 24 You can write
4 × 16 = 40 + 24 = 64 4 × (10 + 6) as
4(10 + 6).
You use the
table to expand
the brackets
4(10 + 6) to get
(4 × 10) + (4 × 6).
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