Применяя свойства сложения, вычислите, (300+85) + 15=300+ (+ ) = (73+48)+27 = 328+(50+522) = 999+(1+600) = 485+648+515= ( + )+648 = 421+526+274 = +( + )= 348 +222 +52 +78= (348 + ) + (222+ ) = 524+307+1476 + 393 = ( + ) + (+ ) =

(300 + 85) + 15 = 300 + (85 + 15) = 300 + 100 = 400 (73 + 48) + 27 = 73 + (48 + 27) = 73 + 75 = 148 328 + (50 + 522) = 328 + 572 = 900 999 + (1 + 600) = (999 + 1) + 600 = 1000 + 600 = 1600 485 + 648 + 515 = (485 + 515) + 648 = 1000 + 648 = 1648 421 + 526 + 274 = 421 + (526 + 274) = 421 + 800 = 1221 348 + 222 + 52 + 78 = (348 + 52) + (222 + 78) = 400 + 300 = 700 524 + 307 + 1476 + 393 = (524 + 1476) + (307 + 393) = 2000 + 700 = 2700