Ajutoooooor dau coroana

1. CCXLIX=249 < 251
2.[(3a+19):5-2] x 11 +2=35 35-2=33 33:11=3
(3a+19):5-2 = 3
(3a+19):5=3+2=5 3a+19=5x5=25
3a=25-19=6
a=6:3=2 a=2
3.210:5=42 .Nr sunt 40,41,42,43,44 care dau 210.
4.Calculeaza: a) 45x3= 135 90:2=45 135+45=180
b) 400x3=1200 1200:4=300(un sfert) 300:2=150(o jumatate de sfert)