standard_description: Fluently add and subtract within 20 using mental strategies. (See standard 1.OA.6 for a list of mental strategies.) By end of Grade 2, know from memory all sums of two one-digit numbers.
problem_activity: Task
Compare each pair of numbers. Write your comparison using $\lt, =,$ or $\gt$ and in words. Explain your answer with a picture.
99 and 100
154 and 231
453 and 428
351 and 354


aligns: no