This week we covered binary/octal/hexadecimal multiplication and division. Remember a key point is to convert to decimal and then back to whatever base you are working with for multiplication and division. We also covered basic syntax of the 2D array. Remember that 2D arrays are arrays of arrays, so each "element" of a 2D array is one array (or one row). (Example: say your 2D array is called arr; when you use arr it will get the first row (or array) of the array. To get a singular value at a particular row i and column j, you need to access arr[i][j]). For-each loops are just designed to access each element of an array. Remember that a for-each loop will only run the number of elements of an array times, and if you use a for-each loop on a 2D array, the variable you made that represents each element in the array will be each row in the array.