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Practice adding two-digit numbers by keeping the tens and ones in their own lanes.
Imagine you have two treasure chests: one has 24 gold coins and the other has 15. How can you find the total quickly without counting every single coin one by one?
Every two-digit number is made of two parts: Tens and Ones. Think of them as living in different houses. In the number , the lives in the Tens house and the lives in the Ones house. When we add numbers like , we make sure the neighbors only visit their own kind! We add the ones together and the tens together. Because the numbers are small, they won't 'overflow' into the next house. This is called adding without regrouping.
Let's add marbles. 1. Look at the Ones: . 2. Look at the Tens: . 3. Put them together: tens and ones makes .
Quick Check
In the problem , which two numbers are in the 'Ones' place?
Answer
1 and 5
The best way to solve these problems is to stack them vertically. This means putting one number on top of the other. You must keep the columns perfectly straight, like buttons on a shirt. We always start adding from the right side (the ones) first. If you start on the left, you might get confused later when math gets harder! By keeping the ones in the ones lane and tens in the tens lane, the answer practically writes itself.
Solve using vertical lanes: 1. Line up the and in the ones column. 2. Line up the and in the tens column. 3. Add the ones: . 4. Add the tens: . 5. The final answer is .
Quick Check
True or False: When adding vertically, you should always start by adding the Tens column first.
Answer
False
Sometimes it helps to visualize addition as jumping down a path. To solve , start at the number on a number line. First, take big 'Ten Jumps' for the tens in the second number. Since has tens, take two jumps of . Then, take small 'One Jumps' for the ones. This helps you see how the number grows bigger and bigger!
Let's solve using jumps: 1. Start at . 2. Jump tens: . 3. Jump ones: . 4. You landed on !
What is ?
If you are at on a number line and you jump tens and ones, where do you land?
In the number , the digit represents 8 ones.
Review Tomorrow
Tomorrow morning, try to explain to a friend why we add the ones column before the tens column.
Practice Activity
Find a receipt or a food box with two-digit numbers and try to add them together using the vertical lane method!