2a=1-1 (i moved +1 to the other side ...coz our goal is to isolate "a", and in order to do this, look for numbers that are freer)(moving the +1 to the other side made it -1)(you just need to remember that when we move any number to the other side it will claim its opposite operation so +1 will turn to -1)
2a=0 (1-1=0)
a=0/2 (now, 2 is being multiplied with a, and to isolate "a" we move 2 to the other side, and this will make to divide ((because the opposite of multiplication is division)) )
To put into a fraction the total is the denominator and the 6 would be the numerator as it is the real diamond then divide the numerator by the denominator move your decimal two places round as needed