Question

calculati folosind factorul comun; b) 53*240+53*760; c) 13*215-13*200; d) 12*625-525*12; e) 83*25-64*25+25*81;f) 72*13-72*5+72*12; g)120*3501+3501*20-3501*40;h) 31*73-31*3+31*29+31

Answer 1

b) 53*240 + 53*760 = 53*(240 + 760) = 53 * 1000 = 53000
c) 13*215 - 13*200 = 13*(215 - 200) = 13 * 15 = 195
d) 12*625 - 525*12 = 12*(625 - 525) = 12 * 100 = 1200
e) 83*25 - 64*25 + 25*81 = 25*(83 - 64 + 25) = 25*(19 + 25) = 25 * 44 = 1100
f) 72*13 - 72*5 + 72*12 = 72*(13 - 5 + 12) = 72*(8 + 12) = 72 * 20 = 1440
g) 120*3501 + 3501*20 - 3501*40 = 3501*(120 + 20 - 40) = 3501*(140 - 40) = 3501 * 100 = 350100
h) 31*73 - 31*3 + 31*29 + 31 = 31*(73 - 3 + 29 + 1) = 31*(70 + 30) = 31*100 = 3100.

Answer 2

B) 53*(240+760)=53*1000=53000 C)13*(215-200)=13*15=195 D) 12*(625-525)=12*10=120 E) 25(83-64+81)=25*100=2500 F)72*(13-5+12)=72*20=1440 G)3501*(120+20-40)=3501*100=350100 H) 31*(73-3+29+1)=31*100= 3100