Solve the following subtraction problem by using the empty n

Solve the following subtraction problem by using the \"empty\" number line methods. (a) 304 - 284 (b) 72 - 38

Solution

a) 304-284

284-----------300----------304

16 4

Therefore,

  304-284 = 16 + 4

= 20

b) 72-38

38-------40---------70---------72

2 30 2

Therefore,

72-38 = 2+ 30+2

= 34