I want someone to further explain to me why is it the right solution step by step please

9. Given the following information, what are the NZDISGD currency against currency bid-ask quotations? American Terms European Terms Bid Ask Bank Quotations New Zealand dollar 7265 .7272 1.3751.1 Singapore dollar Bid Ask 6135.6140 162871.6300 Solution: Equation 5.12 from the text implies SNZD/SGD) SYS/SGD) x S(NZD/S 6135 x 1.3751.8436. The reciprocal, 1VSNZDISGD)S(SGDINZD)11854. Analogously, it is implied that SOZDSGD) = S"(SSGD) x S0NZD$)-6140 x 1.3765 = .8452. The reciprocal, /S(NZDISGD)SYSGDINZD) 11832 Thus, the NZDISGD bid-ask spread is NZDO.8436- NZDO.8452 and the SGD/NZD spread is SGD1.1832-SGD1.1854