| (1)44+37+56, =44+56+37, =100+37, =137; (2)163+49+261, =163+(49+261), =163+310, =473; (3)74+(137+326), =137+(74+326), =137+400, =537; (4)249+402, =249+(400+2), =(249+400)+2, =649+2, =651; (5)189+35+211+165, =(189+211)+(35+165), =400+200, =600; (6)483-236-64, =483-(236+64), =483-300, =183; (7)582-157-182, =582-182-157, =400-157, =243; (8)65×5×2, =65×(5×2), =65×10, =650; (9)15×23×4, =15×4×23, =60×23, =1380; (10)36×25, =(4×9)×25, =(4×25)×9, =100×9, =900; (11)25×125×32, =25×125×(4×8), =(25×4)×(125×8), =100×1000, =100000; (12)35×22, =35×(20+2), =35×20+35×2, =700+70, =770; (13)5×(63×2), =(5×2)×63, =10×63, =630; (14)540÷45÷2, =540÷(45×2), =540÷90, =6; (15)540÷36, =540÷(9×4), =540÷9÷4, =60÷4, =15. |