450 + a = 920 – 40
a = – 40 + 920 – 450
a = 430
x – 340 = 180 + 20
x = 20 + 180 + 340
x = 540
8×b=100-63
8×b=32
b=32/8
b=4
450 + a = 920 – 40
a = – 40 + 920 – 450
a = 430
x – 340 = 180 + 20
x = 20 + 180 + 340
x = 540
8×b=100-63
8×b=32
b=32/8
b=4