Page 21 - TG_G1_CH6_CHRIS

6 - 3 Counting Tens
WARM-UP

On Level

Standard
1.NBT.C.5. Given a two-digit number, Time: 10 minutes
mentally find 10 more or 10 less than
the number, without having to count; WHOLE CLASS
explain the reasoning used.
Material: White Board and marker
Objective Instruction:Write the following two patterns on the board. Ask: Complete each of
the following patterns:
Find 10 more and 10 less than a given 10, 20, 30, 40 …
two-digit number mentally using a 100, 90, 80, 70 …
number line or a hundred chart. 50 , 60 , 70 , 80
60 , 50 , 40 , 30
Essential Question

How can we use skip counting to help
us solve problems?
Counting tens forward after 56 as 66,
76, 86… Counting tens back before Reteach
47 as 37, 27, 17 …

Ready to Go Time: 10 minutes

Say: last lesson you studied 1 less and INDIVIDUAL
10 less, our lesson today is counting Instruction: (Happy Count by tens)
tens. Say: Happy Count by tens the regular way from 0 - 120. Then raise your thump up
and say we start with zero, tell children that each time the thumb goes up, they
count on one 10. When we pause and put thumbs down we count backward by
ten.
0,10,20
20,10,0

0 10 20 (pause) 10 0

Enrich

Time: 10 minutes

INDIVIDUAL
Material: marbles
Instruction: Give one child a bag of 13 marbles. Then give him 3 bags of 10 marbles
each. Say: Record the number of marbles after you open each of the bags.
13 + 10 = 23
23 + 10 = 33
33 + 10 = 43

412