Hi L.!
I hear your fustration girl! I just want to add a few things.
I used a book called "Shepherding a Child's Heart" be Ted Tripp. Every single mom on this planet will run into a child telling a lie. It's just part of our fallen nature. This book helped me alot and my kids are on track. My oldest daughter went thru a short period of lying at about 8, but has overcome it. I used the concepts of the book. It's foundations are Biblical. It works.
This same daughter, also had issues with math in school. And we HOMESCHOOL! She is also good in grammar but not so good in math. She finally, has come to a better point with math and I think it was because of a few things: I repeated her entire 5th grade math this year, We spent more time with math facts drills, and we went at a slower pace.
With my daughter, she was having difficulty fully grasping math concepts, but once i thought she did, we'd move to the next concept. A week later she couldn't do the math problems from the earlier week because she forgot it! She clearly had difficulty with retention. (and math builds on itself.) Another thing is that she would make sloppy mistakes, because she didn't have a clear understanding of the math, and she was painfully struggling SO MUCH that she would try to get through it as quickly as possible just get it over with. Also, she is not math brained so she needed visuals to help her fully grasp it. So basically what was happening is that I was thinking she had the concept because she did a few pages of problems, but she clearly DID NOT fully have the concept. Math is one of those things you have to know it upside down and inside out, and really KNOW it - to know it. It is said that you will know you really understand a concept when you can teach it to someone else.
Right now Your daughter will be able to do the math with your coaching because you are telling her the keys to find the answer. When a math test is performed there is no help, and failure means she hasn't grasped the concepts or she doesn't know what the keys are to find the answer. Possibly her math class is going too fast for her and she is falling behind. Or possibly they are using a garbage curriculum. Possibly it is poor teaching methods.Or possibly the school is just pushing for math that is at a higher level than really should be. I've heard that some schools are starting 2nd graders on muliplication! Seems kinda early to me. Ask her teacher if your daughter raises her hand for math help on a higher percentage than some of the other kids. If she is, then that could be a red flag that she is having trouble following at the pace of the class, and needs more time and help to absorb.
Once a misunderstood math concept is passed and the lesson moves on to the next concept, the block in the wall is missing. Missing blocks can bring the whole wall down eventually. This teacher should have suggested private tutoring or SOMETHING to help a child who is failing test after test.
Missing blocks could be failure to memorize addition and subtraction math facts, not truly understaning place value concepts, or not being able to visualize numbers and their size, and relation to eachother. Also, if the teacher herself doesnt have a good grasp of math she might not be able to teach the concept from different viewpoints- which is a must.
For children that are not math-brained or have poor retention, REPETITION is key. They will need two to three times as much repetition as other children who are "math brained". They will also need more visuals than other kids.
With my 6 yr old, I use both math blocks and a number line. My daughter writes her number line at the top of her paper when doing her math.(It especially comes in handy for algebra concepts, 10+y=16).These are basic tools the school should have taught your daughter to use when doing addition and subtraction. If they don't use them, they are failing your daughter. Children her age can't think abstractly, they think concretely. They need to see and touch what they are working on. Abstract thinking doesn't come until later.
One idea is to replace your daughter's punishment of restriction or having items taken away by having her do math at home on the weekends (with you helping.) I would encourage you to replace the word or feeling of punishment with a feeling of hope, that you are on her team and will be there to help her succeed. (And if her failure truly is because of lack-a-dazyness, this will get her back on track real fast, because no one likes to do math on weekends!)
Math-u-see is a good math program for visual learners. It comes with a DVD tutorial that you can watch together. Each lesson should only run about 15 minutes. Maybe you can buy a book at her grade level- START AT THE BEGINNING OF THE BOOK, even if you are 2/3 of the way through that grade. Go over the concepts and see where she is stuck at. I would do at least 2 pages of each of the 30 lessons. If you find one area where she clearly needs more review, do all 5 pages of that lesson and put your focus there. Work through the summer if need be. Remember, you will know if she has mastered it, if she can explain it back to you.
ps..Math U See has placement tests online.
God bless you and hang in there!