$\text { Đáp án: }$
` 1 13/15 . (0,5)² . 3 + ( 8/15 – 1 19/60 ) : 1 23/24 `
` = 28/15 . 1/4 . 3 + ( 8/15 – 79/60 ) : 47/24 `
` = 28/15 . 1/4 . 3 + (–47/60) . 24/47 `
` = 28/15 . 3/4 + (–47/60) . 24/47 `
` = 7/5 . 1/1 + (–1/5) . 2/1 `
` = 7/5 + (–2/5) `
` = 1 `