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Subtracting multiples of 10
1.NBT.6 • Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range of 10-90 (positive or zero differences), using concrete model or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.
Ruby has 50 books that she wants to read over the summer. She has read 20. How many more books does Ruby have to read?
Can Kala solve this problem using ten frames? 50 -20 = 30
Can Colby solve this problem using a number line? 50 – 20 = 30 50 40 20 30 20 + 30 = 50 40 50 20 30
Which ways show 50 - 20 = 30 1. 2. 20 + ? = 50 3. 20 30 40 50
There are 40 flowers in the vase at the store. Rosa bought 20 flowers to give to her mom for her birthday. How many flowers are left in the vase? Rosa solved it this way: Is this correct? Agree or Disagree 40 – 20 = 20
Juan bought 70 pieces of candy to share with his friends. He decides to give 50 pieces of candy away. Juan solves his problem this way: 50 + 70 = 120 100 30 40 50 60 70 80 90 110 120 20 Is this correct? Agree or Disagree
Leo found 40 pennies in the park. He decided to share them with his friend Mike. Leo gave Mike 10 pennies. How many pennies does Leo have now? Leo solved the problem this way: Is this correct? Agree or Disagree 40 – 30 = 10
The clown had some balloons. He gave away 30 balloons. Now the clown has 40 balloons. How many balloons did the clown have? The clown solved the problem this way: 80 40 50 60 70 30 Is the clown correct?
Use your Number Line to Show: 60 – 10 = 50 0 10 20 30 40 50 60 70 80 90 100
Use your Number Line to Show:90 – 50 = 40 0 10 20 30 40 50 60 70 80 90 100
Use your Number Line to Show:30 – 30 = 0 0 10 20 30 40 50 60 70 80 90 100
Use a double Number Line to Show:100 – 70 = 30100 = 70 + 30 0 0 10 10 20 20 30 30 40 40 50 50 60 60 70 70 80 80 90 90 100 100
Dan spent 40¢ on lunch. • What do you think he bought? Hot dog 30¢ Apple 10¢ Ice cream cone 10¢ Drink 20¢