= 2021.87 + 20,21.100.14 - 2021
= 2021.87 + 2021.14 - 2021
= 2021 ( 87 + 14 - 1 )
= 2021.100
= 202100
xin tiick
2021 × 87 + 20,21 × 1400 - 2021
= 2021 × 87 + 20,21 × 1400 - 2021 × 1
= (2021 × 87) + (20,21 × 1400) - (2021 × 1)
= 175 827 + 28 294 - 2021
= 204 121 - 2021
= 202100