1) 3*12^(-2)=3/(3² *4²)=1/(3*16)=1/48
2) 2^(-3) +6^(1)=1/2³ +1/6=1/8+1/6=7/24
3) 3^(-2) - (-3)^(-1)=1/3² - (-1/3)=1/9+3/9=4/9
4) -2*4^(-3)= - 2/4³= - 2/(2^6)= - 1/2^5 =1/32
5) 3*4^(-2)+2^(-3)=3/(2^4) +1/2³=3/(2^4) +2/(2^4)=5/(2^4)=5/16
6) 0.4^0 -(-0.25)^(?)=1+-
7) -(-2.5)^(-2) +( -2/5)^(-2)= - (2/5)²+(5/2)²= - 4/25 +25/4= - 0.16+6.25=6.09
8) (-3)^(-3) -3.5^(-1)= - 1/3³ - 2/7= - 1/9 - 2/7= - 7/49 - 18/49= - 25/49
9) -4 ^(-3) +( -4/5)^(-2)= - 1/4³ +5²/4²= - 1/64+100/64=99/64=1 35/64
10) -3.5^(-1) +(-2.5)^(-2)= - 2/7+2/5= - 10/35+14/35=4/35
11) 3*(-4)^(-2)+5^(-1)=3/16+1/5=15/80+16/80=31/80
12) (-2.7)^0+(1/7)^??