Page 15 - TG_G1_CH6_CHRIS

6 - 2 1 Less and 10 Less
WARM-UP

On Level

Standard
1.NBT.C.5. Given a two−digit Time: 10 minutes
number, mentally find 10 more or 10
less than the number without having WHOLE CLASS
to count, explain the reasoning Material: 100 chart
used. Instruction:Give a copy of 100 charts to each group of children (small groups) and

Objectives then ask children: Start at 68 and then move one step up.
Color the number you will land on, and state the number 10 less than 68.
Find 1 and 10 less than a given 68 – 10 = 58
two-digit number mentally using a
hundred chart.
Essential Question

How can I find 1 less and 10 Reteach
less?
Sample answer Time: 10 minutes
To find 1 less using 100 chart move
one step to the left and to find 10 less WHOLE CLASS
move one unit up. Material: Unifix cubes and following table
Ready to Go Instruction: Say: Subtract a cube to get one less and a
tower to get ten less. write down the number of cubes in the
Say: Last lessons you studies following and complete the
Number
(one more and ten more), following table. One Less
today you will study one less Ten Less
and ten less than a given
number. Number 20 42 19
One Less 19 41 18
Ten Less 10 32 9

Enrich

Time: 10 minutes
INDIVIDUAL

Material: marbles
Instruction: Say: If you have 65 marbles, and you give ten marbles to one of
your classmates. Ask: how many marbles are with you now?
65 – 10 = 55

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