For anyone that is mentoring young(homescholling, parenting, grandparenting) children the finest inexpensive math tool to use is pennies. Now if you have children that puts things in your mouth be warned that it is very much considered dangerous to swallow pennies. I do not know for sure if this is accurate but the make up of the penny with stomach acid is supposedly more likely to cause problems than when the pennies were all copper.
So we coined the phrase penny math with my children and used the pennies as math manipulatives. Thirty years ago a penny had more purchasing power but in lieu of that one can still let the child keep the pennies and as they add up they can roll them and see the act of saving a little at a time and how it grows. The pennies are laid out in patterns to see adding properties and subtracting properties. The most helpful I think is the relationship of the multiplying and dividing methods and to see pattern that will train the brain to see math patterns in many different things.
My children could do drills with pennies at 7 or eight and had the basic math skills in their head with little effort and their own banks of change. As they rolled the coins and got to spend the money on their own they had a great sense of the concept of how “far” money would go. Studies have shown that spending money is a different emotional experience than using cards or checks. I believe that the connection between earning and spending may be important to help minimize living beyond ones means. I still remember the feeling of my first credit card that I gave in exchange for goods. It was surreal and too easy to disconnect from money in and money out. Dave Ramsey (a financial consultant trainer) has a lot to say about the marketing of credit and the effort to disconnect the individual. The marketing makes using credit a subtle temptation that can get someone into trouble financially. Our economy claims we must live on credit and I think we are going in the wrong direction with that one.
Pennies are great math manipulative and I hope we never get “rid” of them. One day we probably will. Then it would be more expensive but dimes would work to teach the decimal type system and multiples of ten. So have fun with coins and kids.+