Grade 3 - Number
Standard 3.N.7 - Practice solving subtraction sentences to make a specific number up to 20.
Included Skills: Subtraction, Number Properties
Describe and apply mental mathematics strategies for subtracting two 2-digit numerals. • Subtract two given 2-digit numerals, using a mental mathematics strategy, and explain or model the strategy used. • Explain how to use the "taking the subtrahend to the nearest multiple of ten and then compensating" strategy; e.g., to determine the difference of 48 – 19, think 48 – 20 + 1. • Explain how to use the "adding on" strategy; e.g., to determine the difference of 62 – 45, think 45 + 5, then 50 + 12 and then 5 + 12. • Explain how to use the "using doubles" strategy; e.g., to determine the difference of 24 – 12, think 12 + 12 = 24. • Apply a mental mathematics strategy for subtracting two given 2-digit numerals.