wunder beta🧮 Adding and Subtracting Bigger Numbers
Line up digits in columns to add and subtract numbers up to three digits, and pick smart shortcuts like grouping tens or spotting pairs that make ten.
What you’ll learn
- Lining Up in ColumnsAdd and subtract numbers up to three digits with formal column methods, carrying and exchanging when needed.Column methods line up ones under ones and tens under tens, then work from the right. When a column tops 9 you carry a ten (245 + 137 = 382); when the top digit is too small you exchange a ten (352 − 128 = 224).
- Adding Several NumbersAdd three or four two-digit numbers by grouping tens and spotting pairs that make ten.To add several numbers, split each into tens and ones, add all the tens, then all the ones: 23 + 14 + 16 + 25 = 60 + 18 = 78. Hunting for pairs that make ten speeds it up, and adding in any order always gives the same total.
- Fast Within 100Add and subtract fluently within 100 using place value and number-line jumps, and check with the inverse.Within 100, split by place value to add (46 + 37 = 70 + 13 = 83) and jump back in pieces to subtract (83 − 25 = 58). Because addition and subtraction undo each other, you can check any answer by adding it back.
Questions this course answers
In column addition, which column do you add first?
Always start from the ones column on the right so carries move correctly.
What is 245 + 137?
Ones 5 + 7 = 12 (carry 1), tens 4 + 3 + 1 = 8, hundreds 2 + 1 = 3, giving 382.
In 352 − 128, why do you exchange a ten?
The ones digit 2 is smaller than 8, so you exchange a ten to make 12 − 8.
What is 23 + 14 + 16 + 25?
Tens: 20 + 10 + 10 + 20 = 60. Ones: 3 + 4 + 6 + 5 = 18. Then 60 + 18 = 78.
Which pair of ones is easiest to add first because it makes 10?
4 + 6 = 10, a friendly ten that makes the rest of the sum simpler.
What is 46 + 37?
40 + 30 = 70 and 6 + 7 = 13, then 70 + 13 = 83.
Grounded in trusted sources
- Khan Academy Kids
- PBS Kids — early math
- NAEYC — early math learning
- Britannica Kids
Every Wunder lesson is built from real, reputable sources — never invented.
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