`#Sad`
`a,`
`64 × 2021 + 37 × 2021 - 2021`
`= 2021 × (64+37-1)`
`= 2021 × 100`
`= 202 100`
`b,`
`(15)/(16) : (1/2+3/4) - 5/8`
`= (15)/(16) : (2/4+3/4) - 5/8`
`= (15)/(16) : 5/4 - 5/8`
`= (15)/(16) × 4/5 - 5/8`
`= 3/4 - 5/8`
`= 6/8 - 5/8`
`= 1/8`
`c,`
`8,16 : (1,32+3,48) - 0,45 : 2`
`= 8,16 : 4,8 - 0,45 : 2`
`= 1,7 - 0,025`
`= 1,475`
`d,`
`(78×14+50)/(78×15-28)`
`= (78×14+50)/(78×(14+1)-28)`
`= (78×14+50)/(78×14+(78-28))`
`= (78×14+50)/(78×14+50)`
`= 1`
