test exercises

[khan-debug://exercise/finding-1-on-the-number-line](khan-debug://exercise/finding-1-on-the-number-line)
[khan-debug://exercise/understanding-angle-addition-formulas](khan-debug://exercise/understanding-angle-addition-formulas)
[khan-debug://exercise/using-probability-to-make-fair-decisions](khan-debug://exercise/using-probability-to-make-fair-decisions)
[khan-debug://exercise/solving-matrix-equations](khan-debug://exercise/solving-matrix-equations)
[khan-debug://exercise/writing-numerical-inequalities](khan-debug://exercise/writing-numerical-inequalities)
[khan-debug://exercise/creating-line-plots-1](khan-debug://exercise/creating-line-plots-1)
[khan-debug://exercise/creating-line-plots-2](khan-debug://exercise/creating-line-plots-2)
[khan-debug://exercise/adding-and-subtracting-on-the-number-line-word-problems](khan-debug://exercise/adding-and-subtracting-on-the-number-line-word-problems)
[khan-debug://exercise/addition-and-subtraction-word-problems-within-20--level-2](khan-debug://exercise/addition-and-subtraction-word-problems-within-20--level-2)
[khan-debug://exercise/understanding-probability](khan-debug://exercise/understanding-probability)
[khan-debug://exercise/functions-defined-by-integrals](khan-debug://exercise/functions-defined-by-integrals)
[khan-debug://exercise/properties-of-rigid-transformations](khan-debug://exercise/properties-of-rigid-transformations)
[khan-debug://exercise/exploring-rigid-transformations-and-congruence](khan-debug://exercise/exploring-rigid-transformations-and-congruence)