An overview of cross section measurements as a function of jet multiplicities
and jet kinematics in association with ttˉ production is presented. Both
the ATLAS and the CMS collaborations performed a large number of measurements
at different center-of-mass energies of the LHC using various ttˉ decay
channels. Theoretical predictions of these quantities usually rely on parton
shower simulations that strongly depends on tunable parameters and come with
large uncertainties. The measurements are compared to various theoretical
descriptions based on different combinations of matrix-element calculations and
parton-shower models