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

Explanation

To find the square of the numbers 39 and 42 without actual multiplication, we can use the algebraic identities for the square of a binomial.

### Step-by-Step Solution:

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

1. **Rewrite 39**:
We can express 39 as \( 40 - 1 \).
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