823- 523 =
30 + 30 + 30 + 30 + 30 =
120 + 120 + 120 + 120 =
400 + 400 - 20 =
625 + 125 =
30 + 50 + 50 +50 + 50 + 20 =
320 + 320 =
20 X 8 =
1000 - 550 =
650 - 300 =
160
780
480
450
750
640
150
350
250
200
