This task is about using number properties to work out the unknown number.
Show how to find the unknown number (represented by a letter) in each of the following equations.
a) 544 + x – 544 = 238 – 238 + 112
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b) 256 + r = 19 + 172 + 256 – 172
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c) 358 + 13 – 13 + m = 179 + 358 – 179
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d) y + 55 = 678 + 54
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e) 88 + 47 = 86 + 46 + t
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f) 65 – q = 66 – 18
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