Question

120+150=270 240-120=120 400+320=720 370-280=90 340+160=500 420-380=40 решить римскими цифрами

Answer 1

Римскими так римскими.
CXX + CL = CCLXX
CCXL -CXX = CXX
CD + CCCXX = DCCXX
CCDLXX - CCDLCC = XC
CCDXL + CLX = D 
CDXX - CCDLXXX = XL

Answer 2

120 + 150 = 270 270 + 240 - 120 = 390 120 + 400 + 320 = 840 840 + 370 - 280 = 930 90 + 340 + 160 = 590 590 + 420 - 380 = 630 40 in Roman numerals is XL, so the final answer in Roman numerals is XL + XL + XXX = LXX.