Practise makes perfect
Here are 200 equations grouped into 10 groups. Start with the first geoup, and keep going till you get 4 correct in a row. You van then go to the next group. When you get to group 7, you are good to go for this course, and you have won your badge. . If you fancy yourself or like a challenge, keep going. If you complete Group 10 you get your badge cum Lauder.