☰ Contents · Mathematics

Increasing, decreasing and “how many more?”

Lessons 87–90 · 4 lessons · I.V. Repyova, Y.V. Zemlina. Mathematics Grade 1, Parts 1–4. Novda Edutainment, 2023
88

More/fewer (practice)

Textbook Part 3, pp. 30–31
GoalAdd and subtract 10 quickly; move around the hundred square.
New words
hundred square · yuzlik jadvalup / down · yuqoriga / pastgaby 10 · 10 ga
Explanation

Adding 10 only increases the tens digit by 1: 34 + 10 = 44. Subtracting 10 decreases it by 1: 34 − 10 = 24. On a hundred square, one row down = +10, one row up = −10.

Worked examples
45 → down → 55 → down → 65
72 → up → 62 → right → 63
Class activity

Treasure hunt on the hundred square: the teacher gives directions (“from 23, down twice, right once”) and children move a counter to find the treasure.

Practice
1
58 + 10 = ?
2
91 − 10 = ?
3
Hundred square: 3 rows down from 36. Which number?
4
Write the next two numbers: 15, 25, 35, _, _