Addition with carrying within 20 is a fundamental math skill. When we add two numbers and the sum of their digits is 10 or more, we need to carry over to the tens place. For example, when we add 10 plus 5, we get 15, which has 1 ten and 5 units.
Let's learn the step-by-step method for addition with carrying. When we add 8 plus 5, first we add the units digits: 8 plus 5 equals 13. Since 13 is greater than 10, we carry the 1 to the tens place and write 3 in the units place. The answer is 13, which means 1 ten and 3 units.
The visual counting method helps us understand carrying better. Let's add 7 plus 6 using dots. We have 7 blue dots and 6 red dots. When we combine them, we get 13 dots total. We can group 10 dots together to make 1 ten, leaving 3 units. So 7 plus 6 equals 13.
Let's look at common examples of addition with carrying. Nine plus four equals thirteen, which is one ten and three units. Eight plus seven equals fifteen, one ten and five units. Six plus eight equals fourteen, one ten and four units. Nine plus nine equals eighteen, one ten and eight units. The pattern is clear: when the sum is ten or greater, we always carry one ten.
现在我们来练习！试着解决这些问题：7加5等于12，9加3等于12，6加7等于13。记住关键技巧：先用实物练习，记住和大于等于10需要进位，总是检查答案，从小数字开始。进位帮助我们把数字整理成十位和个位，让数学变得更简单、更有条理！