Students should use their experiences from kindergarten and first grade regarding adding and subtracting to within 20. Students should be able to add and subtract facts within 20 with automaticity or with speed and accuracy with little or no conscious effort. Students may use the strategies of doubles, doubles plus or minus 1, counting on, making a 10, hidden 10s, and the communicative property to determine these facts.
Read the two word problems below. You may need paper and pencil to solve each one.a) Amy has a new pack of 10 pencils and 4 pencils from an old pack. She gave 6 pencils from the new pack to her brother. How many pencils does she have left?
b) John brought his marble collection to school. He has 11 blue marbles and 7 red marbles. At school, John lost 3 of his blue marbles. How many blue marbles does he have now? How many total marbles does he have left?
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2.4 Number and operations. The student applies mathematical process standards to develop and use strategies and methods for whole number computations in order to solve addition and subtraction problems with efficiency and accuracy. The student is expected to:
(A) recall basic facts to add and subtract within 20 with automaticity