A simple equation like “8 + 8 = 16” is an example of a double fact in mathematics. Any number that has been twice is a double fact, however they are most frequently used with tiny numbers, usually under 12.
Because they offer a quicker technique to solve addition problems that are difficult to learn, double facts are used by teachers to teach their students. Students can use double facts to solve problems instead than recalling the formula “8 + 9 = 17,” for instance.
In this instance, a learner would be aware that nine is one more than eight and that the double fact of eight is 16. The pupils must then multiply one by 16 to arrive at the solution. In order to get the solution, the learner could also recall the double fact of nine and then deduct one.
The same method also functions with greater numbers. The double fact of 15 is 30, thus if a student tries to figure out the answer to “15 + 18,” they should keep that in mind. The learner must therefore multiply that response by three to arrive at the answer.