×÷9=1000-910 ו9=1000-910 , 100•×=2430-2030 100÷×=2430-2430
1) x : 9 = 1000 - 910 x : 9 = 90 x = 90 * 9 x = 810 2) x * 9 = 1000 - 910 x * 9 = 90 x = 90/9 x = 10 3) 100 * x = 2430 - 2030 100 * x = 400 x = 400/100 x = 4 4) 100 : x = 2430 - 2430 100 : x = 0 x = 100/0 решение не имеет