Tính nhanh: B = 2016 × 2018 – 20172.
Tính nhanh:
B = 2016 × 2018 – 20172.
Tính nhanh:
B = 2016 × 2018 – 20172.
B = 2016 × 2018 – 20172
B = 2016 × 2018 – 2017 × 2017
B = 2016 × (2017 + 1) – 2017 × (2016 + 1)
B = 2016 × 2017 + 2016 – 2017 × 2016 + 2017
B = 2016 – 2017
B = –1.