Answer
a) $\$1,300$ billion
b) $\$680$ billion
c) $\$1980$ billion
Work Step by Step
a) Since the numbers in the given expression, $
2303+(-3603)
,$ have different signs, then subtract the numbers and copy the sign of the number with the greater absolute value. That is,
\begin{array}{l}\require{cancel}
2303+(-3603)
\\=
-(1300)
\\=
-1300
.\end{array}
Hence, the deficit is $
\$1,300$ billion.
b) The conditions of the problem translates to the expression $
2775+(-3455)
.$
Since the numbers in the expression above have different signs, subtract the numbers and copy the sign of the number with the greater absolute value. That is,
\begin{array}{l}\require{cancel}
2775+(-3455)
\\=
-(680)
\\=
-680
.\end{array}
Hence, the deficit is $
\$680$ billion.
c) Adding the deficits in parts (a) and (b) results to the expression, $
-1300+(-680)
.$
Since the numbers in the expression above have the same signs, then add the numbers and copy their common. That is,
\begin{array}{l}\require{cancel}
-1300+(-680)
\\=
-(1980)
\\=
-1980
.\end{array}
Hence, the combined deficit is $
\$1980$ billion.