What is the next number in the series 70, 54, 45, 41?

Concept: In a decreasing-squares number series, each term is formed by subtracting successive perfect squares, taken in descending order, from the previous term.

1. 70 − 42 = 70 − 16 = 54

2. 54 − 32 = 54 − 9 = 45

3. 45 − 22 = 45 − 4 = 41

4. 41 − 12 = 41 − 1 = 40

Cross-check: the squares subtracted at each step — 42, 32, 22, 12 — form a strictly descending sequence of consecutive integers squared, confirming the rule. Extending it by one more step gives the next number in the series.