Emek and Luna were building a bridge across a small stream. They knew the bridge needed 12 blocks, but they had only 8. Luna counted on from 8: 9, 10, 11, 12. They needed 4 more blocks. Emek collected 4 strong blocks, and they added them to the bridge. Together they checked the total: 8 blocks plus 4 blocks made 12. The bridge was complete, so they crossed safely.
Challenges
Challenge 1 of 5
Challenges
Challenge 1 of 4
Hint
Look for a number sentence that starts with 8 and reaches 12.
Luna says they need 4 more blocks because counting on from 8 gives 9, 10, 11, 12. Which number sentence checks that she is correct?
8 + 3 = 118 - 4 = 48 + 4 = 1212 + 4 = 16Correct! Adding 4 to 8 makes the 12 blocks needed for the bridge.
Check which number sentence shows 8 blocks becoming 12 blocks.
Next🎉 Congrats! You got this question!
Hint
Start at 8 and count on 3 numbers.
Emek thinks that adding only 3 blocks to the 8 they had would complete the 12-block bridge. How many blocks would they actually have if they added only 3?
Correct! Adding 3 blocks to 8 gives 11, so the bridge would not be complete.
Count on 3 from 8: 9, 10, 11.
Next🎉 Congrats! You got this question!
Hint
Start with all 12 blocks and take away the 4 blocks that were added.
Suppose Luna wants to check the 12-block bridge using subtraction. Which number sentence shows that 4 blocks were added to the 8 they already had?
12 - 4 = 812 - 8 = 38 - 4 = 412 - 3 = 9Correct! Taking the 4 added blocks away from 12 leaves the original 8 blocks.
Start with 12 and subtract the 4 blocks that Emek added.
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🎉 Congrats! You finished this challenge set!
