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प्रश्न
Evaluate: 20.8 × 19.2
योग
उत्तर
20.8 × 19.2
= (20 + 0.8) (20 − 0.8)
= (20)2 − (0.8)2 ......[ ∵ (a − b) (a + b) = a2 − b2]
= 400 − 0.64
= 399.36
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