Math Facts and Fluency Make a Difference
What is the importance of fluency (speed) in math?
A child will be unable to effectively use certain skills unless learned to fluency. For example, unless a child can accurately answer math facts very rapidly, the child will have undo frustration when doing more complicated math tasks involving that skill. (Long division is impossible if the child cannot quickly do the subtraction subtasks.) How Fluency is Learned Effective teaching research shows that there are four stages to a student's learning. The first stage is the acquisition stage where the goal is helping the child learn the skill accurately. This is the stage of instruction where the child learns how to sound out the word, or to write the correct answer to the math problem is, or to identify the causes of the Civil War. The second stage of learning is the fluency stage where the learner acquires the information at an automatic level. At this stage, when the child sees the word he/she doesn't have to stop and sound it out; when the child has to write a spelling word he/she doesn't have to think about each letter as it is written; when the child solves the long division problem the subtraction portion is automatic. For some school subjects, fluency isn't that important. One doesn't need to explain the causes of the Civil War with more speed. For other subjects such as math, reading, and spelling, fluency is as important as acquisition. After fluency comes the maintenance stage of learning, which is sometimes called "overlearning". At this stage of learning, the goal of instruction is to maintain a high level of performance over time. This is a critical stage for individuals with any type of memory problems. The fourth stage of learning is the generalization stage during which the learner needs to perform the skill at different times and in new situations. This is the part of the learning process when those group activities and hands on projects can actually be helpful if they involve skills that the students have already learned to fluency. 
How Fast
Research shows that to be fluent children should be able to accurately solve math facts at a rate of one per every 2 seconds.
Naturally, if the child has poor fine motor skills or is younger, that has to be taken into account on any written timed test. How to Help
Ideally, your child should practice his math fact every night (about 10 minutes). The goal is to beat the previous night's score. Make it fun. Create a graph showing his PROGRESS. And he will see progress! Also a little reward for each improvement is great. Everyone likes to be a winner.
Parents who have tried this strategy report that their child had fun AND I have witnessed an improvement in their performance.

Math Fluency Worksheets
Group 1:
Addition Math Practice  adding 3 addends
Subtraction Math Practice  23 seconds/problem
Group 2:
Addition Math Practice  adding 4 addends
Subtraction Math Practice
Group 3:
Addition Math Practice  adding double digit and single digit with regrouping
Subtraction Math Practice  subtracting across 0s
Addition Math Practice  adding 3 addends
Subtraction Math Practice  23 seconds/problem
Group 2:
Addition Math Practice  adding 4 addends
Subtraction Math Practice
Group 3:
Addition Math Practice  adding double digit and single digit with regrouping
Subtraction Math Practice  subtracting across 0s
Recommended worksheet sites:
There are FABULOUS websites to download a variety of excellent worksheets.
There are FABULOUS websites to download a variety of excellent worksheets.