(145 × 99 + 145) – (143 × 101 – 143)

(145 × 99 + 145) – (143 × 101 – 143)

= 145 × ( 99+ 1) – 143 × ( 100 – 1)

= 145 × 100 – 143 × 100

= (145 – 143) × 100

= 2 × 100

= 200