Номер 801

5 • y = 80;
y = 80 : 5 = (50 + 30) : 5 = 10 + 6 = 16;
y = 16;
5 • 16 = 80;
80 = 80.

z • 2 = 48;
z = 48 : 2 = (40 + 8) : 2 = 20 + 4 = 24;
z = 24;
24 • 2 = 48;
48 = 48.

300 – x = 299 + 1;
300 – x = 300;
300 – 300 = x;
x = 0;
300 – 0 = 299 + 1;
300 = 300.

x – 545 = 600 – 375;
x – 545 = 225;
x = 225 + 545;
x = 770;
770 – 545 = 600 – 375;
225 = 225.