Hey!
When you raise a number to a power, you multiply that number by itself. (4^2 = 4 * 4 for example) 1.2 * 1.2 = 1.44 That's for the first one.
2^3 + 17 - 3 * 4. ---> 8 + 17 - 3 * 4
8 + 17 - 3 * 4 ---> 8 + 17 - 12
8 + 17 - 12 ---> 25 - 12
25 - 12 ---> 13 Thats for the second one.
9^2 / 3^3 ---> 81/27
81/27 ---> 3 Thats for the third one.
Hope this helps!! ☺♥
