I'm really bad at non-calculator questions - how can I get better at calculations?

Practice is the best way - that being said there are some tricks you can use.It's often easier to change the way you represent a number. For example, consider 99 x 8799 is very close to 100, which is a much easier number to multiply by. If you represent 99 as (100 - 1) it becomes clear that you can just subtract 87 from 9900 to get your answer.Similar tricks exist for addition, for example its generally faster to add 1000 and subtract 11 than it is to add 9989Another trick is that you can change one side of a multiplication to something much easier to multiply and correct for the change you made by altering the other side of the multiplication. For example, consider 33.33.. x 45If you multiply 33.333333... by three, you can get 100, which is much easier to multiply by. To correct for the change you made, you can divide 45 by three. In other words, if you change 33.333 * 45 into 100 *15 ; a much easier calculation which gives you the exact same answer!Similar tricks can be applied to division. For example, it's often easier to divide a number by 10, and multiply it by 2, than it is to divide it by five Consider 4.448/ 5 vs (4.448/10)/2The leftmost of the two calculations would be very difficult to perform without considerable writing, whereas the rightmost is easy. To divide by ten you can move the decimal place one step to the left, then to divide by two you can just half each of the digits).