A dozen minus nine equals several plus 1.
13-9=3+ 1=4
Twelve MINUS eight equals several plus two.
15-8=5+2=7
Twelve minus seven equals several plus three.
Twelve minus six equals several plus four.
A dozen MINUS five equals several plus five.
Addition and subtraction skills:
The division and combination of numbers within 1 and 10 laid a solid foundation for the addition and subtraction of elementary mathematics.
Because the addition and subtraction within 10 is the basis of addition and subtraction calculation in primary school mathematics, just like the formula of multiplication in grade two, let children remember the division and combination of 10 numbers, for example, 2 and 4 make up 6, so that they can know that 2+4 = 6; If 3 and 5 make up 8, we can know that 3+5=8, and so on.
2, learn to split numbers and make a whole ten.
Add and subtract numbers greater than 10, and teach children how to divide numbers to make whole tens, which is the commonly used "ten-filling method", such as 16+3=? Divide 16 into 10 and 6,6+3 = 9, 10+9 = 19.