⇒531−[231÷{43−21×(107−53)}]⇒531−[231÷{43−21×(107−5×23×2)}]⇒531−[231÷{43−21×(107−106)}]⇒531−[231÷{43−21×(107−6)}]⇒531−[231÷{43−21×101}]⇒531−[231÷{43−2×101×1}]⇒531−[231÷{43−201}]⇒531−[231÷{4×53×5−201}]⇒531−[231÷{2015−201}]⇒531−[231÷{2015−1}]⇒531−[231÷{2014}]⇒531−[37÷2014]⇒531−[37×1420]⇒531−[3×147×20]⇒531−[42140]⇒316−310⇒316−10⇒36⇒2
Hence, 531−[231÷{43−21×(107−53)}]=2.