Grade 3 - Number
Standard 3.N.6 - Practice solving addition sentences with two digit numbers.
Included Skills: Addition
Describe and apply mental mathematics strategies for adding two 2-digit numerals. • Add two given 2-digit numerals, using a mental mathematics strategy, and explain or illustrate the strategy. • Explain how to use the "adding from left to right" strategy; e.g., to determine the sum of 23 + 46, think 20 + 40 and 3 + 6. • Explain how to use the "taking one addend to the nearest multiple of ten and then compensating" strategy; e.g., to determine the sum of 28 + 47, think 30 + 47 – 2 or 50 + 28 – 3. • Explain how to use the "using doubles" strategy; e.g., to determine the sum of 24 + 26, think 25 + 25; to determine the sum of 25 + 26, think 25 + 25 + 1 or doubles plus 1. • Apply a mental mathematics strategy for adding two given 2-digit numerals.