Giải thích các bước giải:
a)`254` x `399` - `145` `/` `254` + `399` x `253`
= `(` `253` + `1` `)` x `399` - `145` `/` `254` + `399` x `253`
= `253` x `399` + `399` - `145` `/` `254` + `399` x `253`
= `253` x `399` + `254` `/` `254` + `399` x `253`
= `1` .
b)`5932` + `6001` x `5931` `/` `5932` x `6001` - `69`
= `5932` + `6001` x `5931` `/` `(` `5931` + `1` `)` x `6001` - `69`
= `5932` + `6001` x `5931` `/` `5931` x `6001` + `6001` - `69`
= `5932` + `6001` x `5931` `/` `5931` x `6001` + `5932`
= `1`
