Teacher presentation materials. Unit: 1.4 Numbers to 99 (Grade 1). 1.4 Numbers to 99 Unit Goals Students develop an understanding of place value for numbers up to 99. Section A Goals Add and subtract multiples of 10. Represent the base-ten structure of multiples of 10 up to 90 using towers of 10, drawings, numbers, or words. Section B Goals Add and subtract multiples of 10. Represent the base-ten structure of numbers up to 99 using drawings, numbers, and words. Understand that the two digits of a two-digit number represent amounts of tens and ones. Section C Goals Compare 2 two-digit numbers based on the values of the tens and ones digits, recording the resul