lesson
Updated 1 month ago · 5 views
Imagine you have 23 shiny game cards, and a friend gives you 45 more. How can you find the total of 23+45 written straight across a page without stacking them?
Breaking Numbers Apart
Every two-digit number is built from tens and ones. The number 23 is really 20+3, and the number 45 is really 40+5.
📊A visual diagram showing two number breakdown cards side by side on a light background (#f8f9fa). Left card: '23' splits with two arrows into '20' (shown as 2 vertical blue rods of 10) and '3' (shown as 3 small green unit cubes). Right card: '45' splits with two arrows into '40' (4 vertical blue rods of 10) and '5' (5 small green unit cubes). Clean borders (#e6e6e6), rounded corners (12px), text color #1e2945, width responsive to 350px.
So how do we add these broken-up pieces together quickly?
The Split Strategy
When numbers sit horizontally in a line, you can split each number into tens and ones, add like parts together, and combine the results.
For 23+45, first add the tens: 20+40=60. Then add the ones: 3+5=8.
📊An interactive-style step-by-step horizontal addition diagram for 23 + 45. Top row: '23 + 45' in large text. Curved blue arrow connects the tens digits (2 and 4) down to 'Step 1: 20 + 40 = 60'. Curved green arrow connects the ones digits (3 and 5) down to 'Step 2: 3 + 5 = 8'. Bottom row shows 'Step 3: 60 + 8 = 68' highlighted in a bold summary box with a yellow badge. Text #1e2945, background #ffffff, border #e6e6e6.
Finally, add those two parts together: 60+8=68. That means 23+45=68.
Watch out for a common mix-up: make sure you add tens to tens and ones to ones! Adding a tens digit to a ones digit (like 20+5) mixes up the place values.
What does this look like when we try an even bigger pair of numbers?