Here is an example of math -> ∑i=1k+1i\displaystyle \sum ^{k+1}_{i=1} {i}i=1∑k+1i 123
1(x+a)2=∑k=0n(kn)xkan−k\left ( {x+a} \right )^{2}=\sum ^{n}_{k=0} {\left ( {^{n}_{k}} \right ){x}^{k}{a}^{n-k}}(x+a)2=∑k=0n(kn)xkan−k0