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Phase 5: Place Value

Lessons 86-105 · Phase 5 introduces place value (tens and ones), counting to 100, and addition/subtraction within 20.

Concepts Introduced

SymbolLessonTypeExample
tens86place value10 = 1 ten, 0 ones
ones86place value13 = 1 ten, 3 ones
counting to 5090number rangetwenty-one through fifty
counting to 10095number rangefifty-one through one hundred
addition to 20100operation8 + 7 = 15

Skills

  • Understanding tens and ones
  • Representing two-digit numbers with place value
  • Counting to 100 by ones and tens
  • Skip counting by 2s, 5s, and 10s
  • Adding and subtracting within 20

Tips for Teachers

Place value is the single most important concept in elementary math. Use base-ten blocks or draw tens/ones diagrams. If the child does not understand that 23 means '2 tens and 3 ones', stop and reteach.

What to Expect

By the end of Phase 5, the learner understands place value, counts to 100, and can add/subtract within 20.

Lessons in This Phase

86 tens and ones 87 tens and ones 88 tens and ones 89 tens and ones 90 counting to 50 91 counting to 50 92 counting to 50 93 counting to 50 94 counting to 50 95 counting to 100 96 counting to 100 97 counting to 100 98 counting to 100 99 counting to 100 100 +/− within 20 101 +/− within 20 102 +/− within 20 103 +/− within 20 104 review 105 review