a, 4
b, 100
c, / ko biết là cái j nên ko giải đc
a, 1990 . 1990 - 1992 . 1988
= 3960100 - 3960096
= 4 .
b, ( 1374 . 57 + 687 . 86 ) : ( 26 . 13 + 74 . 14 )
= ( 78318 + 59082 ) : ( 338 + 1036 )
= 137400 : 1374
= 100 .
c, \(\frac{37.13-13}{24 +37.12}\)
\(=\frac{37.\left(12+1\right)-13}{24+37.12}\)
\(=\frac{37.12+37-13}{24+37.12}\)
\(=\frac{37.12+24}{24+37.12}\)
\(=1\)