Sea Shelters
This is a level 3 and 4 number activity from the Figure It Out theme series.
A PDF of the student activity is included.
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choose a mental strategy to solve addition and subtraction problems
solve multiplication problems using tidy numbers and place value
Students can use various methods to find out which place each creature lives in without performing the calculations. These methods include:
• Ones-digit focus
(For example, 245 x 3 will have an answer with a ones digit of 5, and so that sea creature must live in the shipwreck.)
• Estimating the relative size of answer
(For example, 1000 – 176 will have an answer greater than 800, and so that sea creature must live in the coral.)
• Applying place value
(For example, 103 x 8 is (100 x 8) + (3 x 8), which is 824, and so that creature must live in the coral, or 300 + 70 + 8, which is 378, and so that sea creature must live in the seaweed.)
Answers to Activity
Seaweed: b, c, k, l, u, r
Coral: d, e, j, n, s
Kelp: a, g, i, o
Shipwreck: f, h, m, p, q, t