Answers

1. Since they are whole numbers you can just subtract
   255 – 245 = 10
   The ^2 means add two decimal points after the 10 in the positive direction since it’s ^+2

   So 1000

   255^2 =25500
   245^2 = 24500

   25500 – 24500 = 1000

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2. Recall that

   (a + b)² = a² + 2ab + b²

   Then we write

   255² – 245² = (245 + 10)² – 245²

   … = (245² + 4900 + 10²) – 245²

   … = 4900 + 100

   … = 5000

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