First Grade Major Work in Mathematics
Number and Operations in Base Ten
Understand that the two digits of a two-digit number represent amounts of tens and ones.
Compare two two-digit numbers based on meaning of tens and ones digits, recording the results of comparisons with the symbols.
Add within 100, including adding a two digit number and a one digit number, and adding a two digit number in a multiple of ten using concrete models, 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. Understand that adding two digits numbers, one adds ten and tens, ones and ones; and sometimes it is necessary to compose a ten.
Operations and Algebraic Thinking
Relate counting to addition and subtraction.
Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing with unknowns in all positions, e.g. by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.
Understand subtraction as an unknown- addend problem.
Add and subtract within 20 demonstrating fluency for addition and subtraction within 10.
Apply properties of operations as strategies to add and subtract.