271. Calculează prin două procedee: a) (40 + 30) 50; b) (100 - 60) x 40; (20 + 70) x 60; (40 - 20) x 90; (20 + 80) x 90; 40 x (20 + 50);
Răspunsuri la întrebare
a) (40+30)×50=70×50=3500
(40+30)×50=40×50+30×50=2000+1500=3500
b) (100-60)×40=40×40=1600
(100-60)×40=40×100-60×40=4000-2400=1600
(20+70)×60=90×60=5400
(20+70)×60=20×60+70×60=1200+4200=5400
(40-20)×90=1800
(40-20)×90=40×90-20×90=3600-1800=1800
(20+80)×90=9000
(20+80)×90=20×90+80×90=1800+7200=9000
40×(20+50)=2800
40×(20+50)=40×20+40×50=800+2000=2800
Răspuns:
(40 + 30) × 50 = 70 × 50 = 3500
(40 + 30) × 50 = 40 × 50 + 30 × 50 = 2000 + 1500 = 3500
(100 - 60) × 40 = 40 × 40 = 1600
(100 - 60) × 40 = 40 × 100 - 60 × 40 = 4000 - 2400 = 1600
(20 + 70) × 60 = 90 × 60 = 5400
(20 + 70) × 60 = 20 × 60 + 70 × 60 = 1200 + 4200 = 5400
(40 - 20) × 90 = 1800
(40 - 20) × 90 = 40 × 90 - 20 × 90 = 3600 - 1800 = 1800
(20 + 80) × 90 = 9000
(20 + 80) × 90 = 20 × 90 + 80 × 90 = 1800 + 7200 = 9000
40 × (20 + 50) = 2800
40 × (20 + 50) = 40 × 20 + 40 × 50 = 800 + 2000 = 2800
==pav38==