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Unit 6 Learning Goal B: The student will use number relationships to develop subtraction strategies within 100.
* Subtract within 10 with automaticity. (Lessons 6-1 & 6-2) MA.2.NSO.2.1)
The following 6a benchmark targets reflect the work of the unit.
· Subtract within 10 with automaticity (work of Grade 1)
· Subtract two numbers from 11 – 20 with procedural reliability, using an accurate and reliable method that aligns with the students’ understanding.
This benchmark also aligns with Unit 9 where automaticity is expected.
Learner Goal B:
COUNTING ON or COUNT BACK to fluently subtract
6.1 Video strategies to subtract fluently
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MAKE 10: you can make a 10 or use addition to fluently subtract.
One way- decompose an addend to make 10 (15-6=?, 15- 5 =10, 10-1= 9)
another way- use addition to subtract. 6+? =15, count on until you say 15, then count your #s or spaces. 6+?=15, ? = 9
6.2 More strategies to subtract within 20
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You can use BASE TEN blocks to represent and solve 2 digit subtraction equation.
CAUTION- use single neat line to represent a TEN
and single neat and dark dot to represent ones. To help dot in a "ten frame" arrangement. That means 5 on top and 5 on bottom.
6.3 represent subtraction with 2 digit numbers
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Sometimes you have to regroup 1 ten as 10 ones to subtract.
6.4 Represent 2-digit subtraction with regrouping
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You can use bars or jumps on a number line to subtract.
6.5 Use a number line to subtract
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Decompose ONE number to subtract.
6.6 Decompose numbers to subtract
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I will provide number lines to go home in their math baggie and they will have access to a number line during our lessons, too.
You can decompose a number by place value to help solve a 2 digit subtraction equation.
When you adjust numbers to subtract, you add the SAME amount to, or subtract the SAME amount from, both numbers
6.7 Adjust numbers to subtract
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You can solve a subtraction equation by writing and solving a related addition equation.
5.8 Relate addition to sbutraction
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You can solve subtraction equations by using addition.
An equation is true when the values on each side of the equal sing are equal.
5.9 True Subtraction (determine if true or false)
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6.10 Determine the unknow in an subtraction equation
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You can use strategies you kow to determine an unknown in a subtraction equation.
MA.1.NSO.2.1: Recall addition facts with sums to 10 and related subtraction facts with automaticity.
MA.2.NSO.2.1: Recall addition facts with sums to 20 and related subtraction facts with automaticity.
MA.2.NSO.2.3: Add two whole numbers with sums up to 100 with procedural reliability. Subtract a whole number from a whole number, each no larger than 100, with procedural reliability.
On our Unit 6 test we will have questions how to make a 10 or double to subtract.