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Grade 1 Math · Level 6, Grade 2 Bridge

Grade 2 Bridge: Add and Subtract Within 100

How the lesson starts: Grade 2 Bridge: Add and Subtract Within 100

1. Bolt the robot

   Beep boop! Hi friend! Meet Bolt the robot. Bolt packs gears. Ten gears fit in one box. Bolt has 46 gears. Bolt gets 23 more. How many now?

2. Add tens, add ones

   46 + 23 = 40 + 20 + 6 + 3. Add the tens. 40 + 20 = 60. Add the ones. 6 + 3 = 9. Put them together. 69! So 46 + 23 = 69.

3. Take away tens and ones

   Bolt has 68 gears. 25 roll away. 68 − 25 = 60 − 20 + 8 − 5. Tens first. 60 − 20 = 40. Then ones. 8 − 5 = 3. 40 + 3 = 43! Watch out! Ones go with ones.