Find the square of the following numbers without actual multiplication.(i)             39          (ii)     42

Explanation

To find the squares of the numbers 39 and 42 without actual multiplication, we can use the algebraic identity (a ± b)² = a² ± 2ab + b².

### Step-by-Step Solution:

**(i) Finding the square of 39:**

1. **Express 39 in a convenient form:**
We can write 39 as \(40 - 1\).
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