15, 16, 17 minus a number
1.1. Knowledge to remember
1.2. Math forms
Form 1: Calculate
– Set alignment.
– Perform subtraction in turn from right to left, when the unit row of the number being subtracted is not enough to subtract, you need to perform the subtraction with memory.
Form 2: Find unknown value – Find x.
To find the unknown term, subtract the known term from the sum.
– To find the number to be subtracted unknown, we take the difference plus the minus number.
Form 3: Math Quiz
– Read and analyze the topic
– Find the solution of the problem: Notice that the problem has the keywords “reduce”; “remaining”… usually uses subtraction to find the solution.
– Presentation of the problem.
– Check the solution and the results you just found.
1.3. Solving Textbook Exercises
Perform the subtraction and then fill in the blank with the result.
Each number 7, 8, 9 is the result of which calculation?
– Do the math
– Match the calculation with the appropriate number