Find the following values without a calculator.
Give your answers in this manner. (Eg 1, 2, 3, 4)
- 900 + 70 + _____ = 971
- 8000 + _____ + 80 = 8580
- _____ + 80 + 5 = 8085
- 90000 + _____ + 7 = 91407
(a)
900 + 70 + _____ = 971
970 + _____ = 971
971 - 970 = 1
(b)
8000 + _____ + 80 = 8580
8080+ _____ = 8580
8580 - 8080 = 500
(c)
_____ + 80 + 5 = 8085
_____ + 85 = 8085
8085 - 85 = 8000
(d)
90000 + _____ + 7 = 91407
90007 + _____ = 91407
91407 - 90007 = 1400
Answer(s): 1, 500, 8000, 1400